Continental intercalaire

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Published with the assistance of the NATIONAL CENTER FOR SCIENTIFIC RESEARCH


MEMOIRS No. 88A, P. 1 TO 57, PL. I TO XI

No. 88B, P. 1 TO 34, PL. I TO VI


















A. F. de Lapparent.




F. Gorce.

MEM. GEOL. SOC. OF FRANCE. — N. S. — VOL. XXXIX. — 1 MEM. NO. 88A — 1


















The existence of remains of great fossil reptiles in the Saharan continental series was discovered and noted by several of the first explorers. Indeed, more than fifty years ago F. Foureau [1904] and E. Haug [1904] made known that there were remains of fishes and crocodilians and a fragment of dinosaur vertebra, recovered in 1893 in the Djoua during F. Foureau’s memorable missions. Then R. Chudeau [1907] noted the presence of reptile bone remains in the Marandet cliff, Niger in the course of his immense journeys.

A more outstanding discovery is that announced by Depéret and Savornin [1925, 1927], describing two megalosaurid teeth recovered by Captain Burté at Timimoun. Thereafter, Bourcart and Keller [1929; cf. Augiéras, 1931] noted in passing some large dinosaur bones at Tilemsi, while V. Pérébaskine [1933] discovered a sauropod vertebra in the Ibelrane cliff, Soudan.

However, neither C. Kilian nor N. Menchikoff had occasion to find vertebrate fossils during their bold explorations. Only the rich Baharija locality, in the Egyptian desert, revealed rich spoils to the missions of the Munich museum, which E. Stromer and his collaborators published little by little from 1914 to 1938.

It was in 1946, as soon as beginning some remote missions in Africa again after the war could be thought of, that Mr. N. Menchikoff proposed for me to go and prospect the Gourara and Touat. On his advice, some indications gave hope that the sandstones of Timimoun could reveal dinosaurs, because A. Meyendorff, having tragically disappeared in 1942, had recovered reptile bones at several places in the Continental Intercalaire of the Gourara [Meyendorff, 1938]. Thus nine missions were made into the Great Desert between 1946 and 1959. The memory of the first excursions evoked the Sahara of former times, where one walked with the regular step of the camels, going during the weeks from “pasture to pasture” in perfect solitude. In contrast, the last trips benefited from better-equipped missions, where all-terrain vehicles—Jeep, Land Rover, and Power Wagon—permitted astonishing excursions across the Sahara of today.

* *
Two voyages allowed me to explore initially the long band of Continental Intercalaire that girdles the Hammadas of the Tademait and Tinrhert (fig. 1): from November 1946 to January 1947, for the Gourara, Touat and Tidikelt; from November 1947 to January 1948, for the Djoua from Fort Flatters to Ohanet, then from this point up to Edjelé Tan In Azaoua, which no geologist had yet reached [Lapparent, 1949b].

Alerted by a passage of Pervinquière signaling fish remains in extreme southern Tunisia, and thanks to facilities that Mr. G. Castany—then director of the Geological Service of Tunisia—procured for me, I was able to realize two consecutive missions (January 1951 and February-March 1952) all along the Dahar cliff and up to Tripolitania, discovering at several points some dinosaurs of great interest.

Subsequently, thanks to the friendliness of the officers of Tamanrasset, I made a fruitful journey to Tamesna, far south of the Hoggar, in February 1953.

Then, from December 1953 to February 1954, I visited the Niger series in some detail, with the assistance of geologists J. Greigert and F. Joulia; some important dinosaur localities were discovered and studied in these regions. In contrast, I did not find reptile remains in the vast spaces of the Tibesti, Borkou, and Erdis, which I traversed with the geologists of the Borkou-Ennedi-Tibesti mission from the A. E. F. Geological Service from December 1954 to February 1955.

Finally, I returned in February 1958 to the region between Ohanet and Edjelé, profiting from the great facilities that the petroleum bases of the Company for Research and Exploration of Petroleum in the Sahara (C. R. E. P. S.) currently offered in this region, formerly so difficult to access.

This memoir has already been presented during the meeting of the Geological Society of France, when Mr. André Cornet of the Hydraulic Service of Algeria invited me to a rapid but full-interest tour in February-March 1959. Thanks to this occasion, I was able to visit the In Tedreft locality with A. Cornet and G. Busson, at the beginning of In Guezzam. Subsequently, we traversed south of the Tanezrouft under the guidance of Mr. Bourgeois; then the northern part of Tilemsi that extends northwest of Tessalit. Before the manuscript does not leave an impression, I was able to hold account of these new observations and important discoveries made at In Tedreft [Lapparent, 1959].

* *
Always accommodated well in the Sahara, I have no lack of interest in the research of the vertebrate fossils by several people who then sent me interesting elements.

Mr. J. Hugot, teacher at Aoulef, and Mr. Orengo, resident at Timimoun, recovered with patience in these two localities some elements that they addressed to me spontaneously. To Captain Archier we owe the discovery of the Tamesna localities and the organization of my 1953 mission. I also acquired several dinosaur bones, recovered on the one hand at In Abangarit by adjutant Pouillet, on the other south of Agadès by Captain M. Mareschal.

R. Karpoff announced his observations to me regarding the large dinosaur bones from Tilemsi. Ph. Renault accompanied me for several weeks at Tamesna, and G. Busson in the regions of Alrar and Zarzaïtine, then at In Tedreft and Tilemsi. F. Gautier sent me elements from In Tedreft and then wanted very much to lead me to the locality. Geologists Ph. Lefranc and H. Faure recovered with sagacity the remains of fossil reptiles in new or difficult to access regions. Finally, the petroleum geologists who traversed the vast zones of the Sahara in all directions naturally encountered new localities: Cl. Sallé, Ph. Deffrene, R. Nyssen, J.-C. Chavand, M. Gillmann, above all F. Nougarède and P. Claracq, thus gave me bones and teeth of real interest.

On his side, Abbey R. Lavocat traversed the Hammadas of southern Morocco from 1947 to 1950, and discovered some important and varied remains of dinosaurs in the Kem Kem region which he studied, and which will have to be compared with our own finds. He also made a mission to Tilemsi in 1953.

In spite of the fragmentary state of the objects thus amassed during twelve years, I have judged that the moment has come to publish that which concerns the dinosaurs of the Continental Intercalaire of the central Sahara. But it can be hoped that more forceful prospecting in the Great Desert will lead to the future discovery of new remains of fossil reptiles, which will complete the non-negligible knowledge that we have at the current time.


* *
Paleontological missions to the Sahara could not be undertaken without multiple assistances, ensuring financing on the one hand, progression and protection in the desert on the other.

My recognition initially goes to Mr. N. Menchikoff, who incited me to undertake my first voyage to the Sahara and then encouraged me effectively each time to specify a new project.

Numerous official organizations ensured me the necessary subsidies on several occasions, and I thank them for it: the Center for Saharan Research of the National Center for Scientific Research (Mr. N. Menchikoff), the Institute for Saharan Research of the University of Algiers (Mr. R. Capot-Rey), the Geological Mapping Service of Algeria (Mr. G. Bétier), the Hydraulic and Rural Equipment Service of Algeria (Messrs. Drouhin and Cornet), the Geological Service of Tunisia (Mr. G. Castany), the Federal Director of Mines and Geology of A. O. F. (Mr. L. Marvier), and the Geological Service of A. E. F. (Mr. J. Nicault and also Mr. M. Nicklès). Finally, the services of the C. R. E. P. S. facilitated with good grace the 1958 mission starting from the Maison Rouge base established near Edjelé, and those of the Company for the Exploration of Petroleum (C. E. P.) accommodated me in their sector of the Tinrhert.

Not being able to cite all those who offered me their traditional hospitality, I want to at least address my most particular memory to Mgr. G. Mercier, bishop of the Sahara, to the White Fathers of Adrar, El Goléa, and the I. B. L. A. at Tunis, to Mgr. Quillard, apostolic vicar of Niger, and to the Fathers of the Zinder mission.

In citing several names among the soldiers and administrators who facilitated my attempt and often were interested in it, I would like to associate all the others who aided me in diverse degrees: General Quénard, as Commander of the territory of Aïn Sefra; Colonel Thiriet (†1956), then Commander of the territory of Oasis; Colonel Vigourous, at Ouargla; Commander P. Le Liepvre, at In Salah and then Rhat; Commander J. Lecointre, at Aoulef and subsequently at Tamanrasset; Captain L. Archier, at Tamanrasset; Lieutenant G. Mercadier, who received me at Timimoun; Lieutenant C. Allibert at In Salah; the officers of Tatahouine and Rémada; Mr. Périé, Circle Commander at Agadès; Commander Ladurelli and Mr. Mora, at Largeau; Captain Decamp, at Fada; G. Touron, faithful companion at Tamesna; finally Dr. Amlot, Lieutenant-Doctor at Rhat in 1947-1948, who devoted himself to me during many days after a dramatic accident.

This incomplete enumeration at least underlines the close solidarity of the desert, in the good as well as the bad moments.

Naturally my memory also goes to all the faithful guides—Arab, Touareg, and Toubou—who always ensured good conditions on demanding routes and sometimes contributed to the discovery of fossils.

Let me add that such fossils, simultaneously fragile and heavy like the careful illustration of a memoir of this type, required diverse help. I must note all the help that was brought to me for these realizations, as much Mr. Solignac, molder, as Messrs. Leriche, Mémin, and M. Potiquet, photographers.


The Sahara or Great Desert is an arid zone nearly 2,000 km wide, saddled on the Tropic of Cancer, that traverses Africa from west to east, from the Atlantic coast to the Red Sea (fig. 2). We will agree to delimit the central Sahara, to which the present study refers, as the quadrilateral comprised between Colomb-Béchar, Tripoli, Gao, and Lake Chad, for a surface of some 2,500,000 km2 (fig. 2 and 3). But the dinosaur terrains only naturally cover part of this extent (fig. 3).

To the north, the limit between the Sahara and Barbary is well marked topographically and geologically by the “Saharan flexure”, from Agadir to Biskra. From this locality, we keep the Biskra-Gabès line as the limit of the Sahara; it leaves a “Tunisian province” to the north that recent studies have shown to be distinct from the Barbary proper.1

To the south the Sahara does not have as clear a limit [Capot-Rey, 1953, p. 16-35]. It is generally a little near the level of the 16th parallel where the desert proper passes into the savanna over several dozen kilometers, although, according to the abundance of the rains, the Savannah and desert can encroach alternatively on one another in a sometimes considerable manner.

I. Distribution and nomenclature of the localities.
A glance thrown on the maps (fig. 2 and 3) shows the distribution of thirty dinosaur localities that are currently known in the central Sahara. They are grouped, not randomly, but in two zones, situated on either side of the Tropic of Cancer and corresponding to large outcrops of the “Continental Intercalaire”.

The northern zone includes the 5 localities of the Dahar cliff in Tunisia and Tripolitania on the one hand; the 11 localities ringing the Tademaït and Tinrhert on the other.

The southern zone includes 17 localities, of which 13 are found distributed in the cliff or plain of the Soudanese and Nigerien Sahara. They are enclosed by one locality on the eastern border and one on the western border of the Aïr, and by two on the western border of the Adrar des Iforas.

Moreover, figure 2 emphasizes the fact that, for the moment, apart from the central Sahara, only two dinosaur localities are known all in all, rather rich it is true: Baharija in the eastern Sahara and Kem Kem in the western Sahara (see the summary table, p. 45).

Besides, the word locality must be extended here in a slightly special manner. In the absence of precise toponymy, which often happens in the case of immense uninhabited and flat expanses, several fossiliferous points could be united under a single name. Thus the In Abangarit localities are distributed in a zone 20 km wide and more than 30 km long. Similarly, the zone of the El Rhaz localities, found by H. Faure in Niger, extends over 120 km. And in southern Morocco, by “dinosaur localities of Kem Kem” R. Lavocat [1952a] means a 250 km band along which a few fossil bones are found everywhere. But each time that a more varied topography favored a more abundant toponymy, I have specified the name of the fossiliferous place as much as possible. Here is the alphabetical list and enumeration of the localities, corresponding to the map in fig. 3:

No. 1. Agadès: 35 km south

2. Agadès: 16 km southeast

3. Alrar

4. Aoulef Cheurfa

5. Chebbi: Aïn Cheikh

6. Chebbi: Oulad Yahia gour*

7. Chenini

8. Déhibat

9. Djoua: Tab-Tab

10. Djoua: 120 km east of Fort Flatters

11. Ebrechko

12. El Rhaz

13. Giado

14. Guermessa

15. Ibelrane

16. Ifayen Ignère

17. Iguallala

18. In Abangarit

19. In Akhamil

20. In Gall

21. In Salah

22. In Tedreft

23. Rémada: Kanboute

24. Tébéhic: Soureya

25. Téfidet

26. Tiguidi: Marandet

27. Tiguidi: Zinder piste*

28. Tiguidi: Irayen

29. Tilemsi 1

30. Tilemsi 2: Tikarkas

31. Timimoun

32. Zarzaïtine: east of ZR.2

33. Zarzaïtine: Maison Rouge cliff

II. Description of the localities.
A) LOCALITIES OF THE DAHAR CLIFF (EXTREME SOUTHERN TUNISIA AND TRIPOLITANIA). — The map (fig. 4) indicates the position of five places along the Dahar cliff that have revealed dinosaurs. When we undertook its exploration in 1951, dinosaurs had not yet been noted there, rather only some fish scales ([Pervinquière, 1912]; in fact, the remains of fishes, and also crocodiles and turtles, are much more abundant than those of dinosaurs.

This 500 km long cliff, with slopes often covered again by rockslides that paste the slopes under the already desert climate, is not so favorable to paleontological researches. For a first reconnaissance, we proceeded in the following fashion. Leaving the principal pistes, we examined the slope of the cliff with binoculars; thus we chose the ravines skirting the falls or, better still, some small promontories or some gour detached in front, on which the clays and sandstones are more widely exposed. We next went up to the foot of the cliff in the Land Rover; then we climbed the slope on foot, attentive to the gravel horizons or conglomerates, which are generally, but not always, revealed to be the richest. We thus methodically “probed” the cliff at numerous chosen points, and proceeded where it was revealed as fruitful; but it is natural that a first prospecting must let some localities escape that are yet to be found.

GUERMESSA (no. 14). — The case of this locality precisely illustrates what I have said. The isolated gara* that is encountered east of the village shows well some bone remains, but the rockslides there are too developed. Next we went a little more to the south (Djebel el Haddada on the 200,000 scale map of Tunisia, Foum Tatahouïne sheet), where some dismantled gour provide better exposures. There, a conglomerate revealed rather numerous remains of theropod and sauropod dinosaurs, along with silicified wood and crocodilian teeth.

CHENINI (no. 7). — Good exposures are present in this sector, in the gour that precedes the village of Douiret: a sandy zone at mid-height contains numerous trunks of silicified wood, and a conglomeratic level shows bones and teeth of fishes and reptiles. A theropod tooth and the remains of a large turtle were found in the gypsum beds of the cliff between Douiret and Chenini. But the richest locality is a bone bed, localized as a torrential delta in the clays, situated at Er Roua on the piste from Tatahouïne to Chenini.

RÉMADA: Kanboute (no. 23). — We went from the military post of Rémada to examine the exposures of Gara Kanboute, which attracts attention by its isolation 7 km to the southwest (Pl. I, fig. 3). Entirely at the top of the continental series, only several meters under the marine Cenomanian, we found a sandstone very rich in vertebrates; an Iguanodon tooth was recovered there, to my surprise.

Pervinquière noted the Segdel region, 10 km south of Rémada, as concealing some vertebrate remains. We found there a similar section to that of Gara Kanboute, with some remains of fishes and crocodilians at the same level, but no dinosaurs. In the Krechem el Hanana promontory, halfway between Rémada and Déhibat, we found only several crocodilian teeth.

DÉHIBAT (no. 8). — The environs of Déhibat are notched with deep ravines that are very favorable for prospecting; at several levels, silicified or ferruginous wood, remains of abundant fishes, teeth of crocodiles, and poorly determinable dinosaur bones are recovered, especially on the slopes of the Touil Déhibat and Garet er Rehi. The interest in this locality is to permit restoring—more easily than elsewhere—a complete section of the continental series comprised between the marine Upper Jurassic and the marine upper Cenomanian (fig. 5, section A). However one realizes that the same vertebrate fauna is encountered at different levels, sometimes at the summit (Kanboute and Déhibat), sometimes in the middle (Chenini), and sometimes toward the base (Déhibat) of the continental series. This is precious for fixing the Lower Cretaceous age of this fauna; but at the same time this shows that it was illusory to want to distinguish the stratigraphic sections in this series with the aid of vertebrates.
GIADO (no. 13). — A very similar section is observed in the cliff passed in Tripolitania, and we have recovered some vertebrates, notably fish scales, already noted by the Italian authors, at Nalut, Giado, Iefren, and Garian. Alone, toward the middle the Giado cliff has furnished us some dinosaurs in the form of a tooth and a theropod bone. However, it seems that the Tripolitanian zone is less rich in vertebrates than extreme southern Tunisia.
B) LOCALITIES OF THE GOURARA, TOUAT, TIDIKELT, DJOUA, AND THE OHANET-BOURARHET REGION. — All the geological maps of the Sahara reveal a continuous band of clayey-sandy terrains that form the slope and foot of the cliff girdling the Tademaït and Tinrehrt. The Gourara, Touat, Tidikelt, and Djoua are depressed zones dug principally into the Continental Intercalaire series. Between Ohanet and Bourarhet are extended vast sandy plateaus where one begins to foresee a more complete stratigraphy than in the preceding regions. The dinosaur localities are relatively numerous throughout this central Sahara zone, and we describe them summarily from west to east (fig. 6).
TIMIMOUN (no. 31). — The topographic disposition and the succession of terrains are a little different here than those of the Dahar cliff (fig. 5, section B). The Cenomanian-Turonian border of the Tademaït plateau is found moved back due to erosion to 50 km east of Timimoun (Moungar in Zouz); and the upper part of the Continental Intercalaire is essentially clayey: these are the El Goléa clays [J. de Lapparent, 1937] that never contain vertebrates. It is only the base of the continental series that will be fossiliferous here [Lapparent, 1947]. The vertebrate remains were found nearly exclusively in the spoils of the wells of the Amerhaïr foggara*, either by the first works by Captain Burté in 1924, by ourselves in 1946, or afterward by Mr. Orengo. The periodic re-digging of the foggara canal indeed starts with a conglomeratic level with yellow quartz pebbles, some quartzite pebbles, rounded silicified wood, and rather abundant vertebrate remains: fishes, crocodiles, turtles, and sauropod and theropod dinosaurs. The other foggaras, so numerous around Timimoun, provided nearly nothing except a large fragment of dinosaur bone near Oulad Noun. The Amerhaïr foggara is the most productive in fossils (fig. 7), not only because of its prominence (it is 7 km long, with numerous wells spaced every 10 m), but above all because it goes up beyond the first sandy cliff and thus re-covers the principal fossiliferous level, which most of the others do not reach.

The Adrar region has only furnished some small fragments of insignificant bones; we found the largest there in the spoils of the Reggan foggaras. But the best come from the CHEBBI region: Aïn Cheikh (no. 5) and the Oulas Yahi gours (no. 6); it is a large sauropod bone found in place in the sandstone immediately discordant on the Precambrian or Paleozoic.

AOULEF (no. 4). — Thus one arrives at the Aoulef Cheurfa foggara, which delivered reptile bones in abundance. Above all these are the remains of an enormous crocodile, a new species that will be described additionally under the name Aoulef crocodile; but there are also theropod and sauropod bones. The spoils of the Akabli foggara also gave us fragments of reptile bones.

At IN SALAH (no. 21), we observed bone fragments in the sandstones of several buttes to the north, on the El Goléa piste. But we did not have anything determinable at this locality, until the day when Captain Mourret agreed to give us, via Mr. Capot-Rey as intermediary, various bones of a large sauropod discovered in 1957-1958. Recently, Lieutenant C. Allibert found sauropod vertebrae (Pl. XI, fig. 3) in this locality, situated in the clayey-sandy cliff 17 km north-northeast of In Salah.

DJOUA (nos. 9 and 10). — The Djoua valley is relatively rich in vertebrate remains east of Fort Flatters. Dinosaurs were recovered at two points: at Tab-Tab (no. 9) (Pl. I, fig. 1) by F. Foureau himself, and 120 km east of Fort Flatters by F. Nougarède.

IN AKHAMIL (no. 19). — In the gour situated south of In Akhamil, since 1947 we have discovered a fossiliferous band in the greenish sandy clays: numerous fish teeth, crocodile bones, and a large sauropod femur.

ALRAR (no. 3). — The same band is very fossiliferous toward Alrar for a distance of 90 km. But beyond, according to geologist J. Ph. Lefranc, hardly any vertebrate localities are encountered east of the frontier, in the Fezzan territory; however, J. Ph. Lefranc and J. M. Freulon noted bone fragments in the red sandstones around Sabha.

In contrast, descending south of Alrar, dinosaurs are found at several levels in the great continental series, so difficult to date, that is developed between Ohanet and Bourarhet (fig. 8). We note these significant benchmarks.

Below the quartzitic flagstone that crowns the Taouratine series, G. Busson showed us some fragments of sauropod bone in the red sandstones, 10 km south of the In Akhamil locality.

But above all, in the region of the ZARZAÏTINE plateaus (Pl. I, fig. 2), 11 km east-northeast of petroleum wells ZR.2 (no. 32), the C. R. E. P. S. geologists discovered some bones belonging to a very large sauropod and probably a single individual: sacrum, tibia, metacarpals, and phalanges. The locality belongs to the Taouratine series.

Finally, Mr. P. Claracq recently recovered two teeth of Teratosaurus associated with some stegocephalian bones at the summit of the sandy ZARZAÏTINE cliff, above the Maison Rouge (no. 33); it is a lower stratigraphic level than all the preceding ones and one that had not yet furnished fossils.
C) LOCALITIES OF SOUDAN AND NIGER. — South of the Tropic of Cancer, the same geological structure present to the north is found with an astonishing symmetry. Thus inversely, from north to south, the following succession is observed corresponding with as many natural regions (fig. 3):

— the Precambrian base of the Hoggar, with its two large processes, the Adrar des Iforas and Aïr;

— a zone of sandy Paleozoic plateaus, the southern Tassilis;

— vast regs* covering depressed regions, established sometimes on the upper Paleozoic, most often on the clays and sandstones of the Continental Intercalaire [Lambert, 1932-1933];

— a cliff with multiple steps crowned by the marine Upper Cretaceous1 [Furon, 1935].

It is thus in this cliff and the plains which extend to its foot that the seventeen localities are found which remain for us to enumerate (fig. 9).

TILEMSI 1 and 2 (nos. 29 and 30). — At the western border of the Adrar des Iforas, the Continental Intercalaire goes directly to contact the Precambrian* without interposition of Paleozoic sediments. The great north-south Tilemsi depression is principally clear in the clays and sandstones that break through the sproutings of the base. In this region the post-Cretaceous tectonic movements are observed to be particularly emphasized, which locally have raised the Continental Intercalaire and marine Cretaceous to the vertical [Cornet, 1948].

Some large sauropod bones, discovered during the Augiéras-Draper mission halfway between Tessalit and Gao (locality no. 29), were noted by J. Bourcart and A. Keller [1929]. But the widest outcrops of the Continental Intercalaire are developed northwest of Tessalit, where. R Karpoff found bones in 1948, 115 km northwest of this locality. R. Lavocat and S. Rouaix found the place named Tikarkas (locality no. 30): it furnished some sauropod long bones and vertebrae. Moreover, they observed large sauropod bones 35 km further west, near the point marked Enaouallen-ouallen.

With A. Cornet and G. Busson, we returned to the Tikarkas locality in 1959, which appeared to us exhausted. But in a sandy relief 4 km south, we found long bones and a large sacrum of a sauropod, with a crocodile and an entire turtle.

Notable sandstone outcrops of the Continental Intercalaire are known south of Tanezrouft, recently studied by Mr. Bourgeois. Fishes (Ceratodus, Platyspondylus foureaui) have been recovered in the Ilaferh region. On the other hand, some calcareous sandstones outcropping on the reg at 28 and 32 km northeast of Guernène have furnished several bones of indeterminate dinosaurs, a rather abundant crocodile, and calcified wood. The interest of these recent works (1958 and 1959) is to show the extent of the reptiles of the Continental Intercalaire up to the western border of the Hoggar.

IBELRANE (no. 15). — The Cretaceous cliff north of Menake was described by V. Pérébaskine in his thesis [1933, p. 115]. He noted there in passing a 14 cm long sauropod vertebra, collected south of Ibelrane. We have not visited this locality; but there was without doubt interest in further prospecting the entire Continental Intercalaire zone east of Gao.

In contrast, we have brought our attention to the territory of Niger, where fourteen interesting localities are now known, whereas a single one was noted there prior to 1953.

IN ABANGARIT (no. 18). — The best fossil reptile localities of the central Sahara are those of the In Abangarit region, found by Captain L. Archier. We studied them in 1953, through a series of camel trips organized at the outset from a most primitive Touareg encampment [Lapparent, 1953c]. Bones and teeth are abundant in certain zones that seem to correspond to fluviatile deltas. The dinosaurs there are more varied than everywhere else in the central Sahara; the frequency of large carnivorous theropod teeth are noted. Stratigraphically, the In Abangarit series is situated in the upper part of the Continental Intercalaire, a little below the Cenomanian-Turonian.
IGUALLALA (no. 17). — At the same stratigraphic level is found the interesting locality of Mount Iguallala, where J. Greigert led us and which revealed three species of sauropods; the exigencies of a tour in these far countries did not allow us to explore this abundant locality sufficiently: it merits being revisited. Several bones were also found on the reg around Mount Kassot, 80 km north-northwest of Mount Iguallala.

IN TEDREFT (no. 22). — The In Tedreft locality is situated lower in the Continental Intercalaire. It was discovered by accident in 1958 during a petroleum reconnaissance mission by geologists Kieken, Nyssen, and F. Gautier. This last agreed to lead us to this rather difficult to find point [Lapparent, 1959]. The best way to go there is to follow the Agadès piste for 73 km on the Tamesna reg starting from In Guezzam; at the “Agadès 417 km” sign, take a right-angle turn northeast for 28 km. Clayey-sandy buttes covered with bone fragments are found on the eastern side of the Oued Timmersoï, approximately 15 km west of the In Tedreft well. There we recovered theropods, in particular elements of the genus Elaphrosaurus, and some very abundant sauropod bones.

Moreover the region comprises other fossiliferous points. We recovered crocodile and dinosaur bones in a small elongate relief 15 km from the “Agadès 417 km” sign. On the reg 8 km from this sign, numerous dispersed dinosaur bones are noted, and even the entire braincase of a sauropod, unfortunately extremely dislocated.
IN GALL (no. 20). — 1 km north of In Gall, at the foot of the clayey-sandy buttes, we discovered with J. Greigert, and then exploited with F. Joulia, a good locality where the bones of large sauropods are numerous (Pl. II, fig. 1), in particular the foot bones. There it resembles a cemetery of dinosaurs, which perhaps mired themselves in marshes, because they are found in the red clays and not in the sandstones. These “Irazer clays” belong to the lower part of the Continental Intercalaire.

In this same horizon, we encountered dinosaurs at other points located further east, where moreover some individualized sandy lenses are seen. We cite principally: AGADÈS: 35 km south (no. 1); AGADÈS: 16 km southeast (no. 2); IFAYEN IGNÈRE (no. 16) (fig. 10).

The localities of the TIGUIDI cliff are situated a little higher stratigraphically: Marandet (no. 26); Zinder piste (no. 27) (Pl. I, fig. 4); Irayen (no. 28). It is the same in the EBRECHKO promontory (no. 11), which furnished more especially numerous theropod teeth; and also the Soureya buttes north of the TÉBÉHIC well (no. 24), which contain rather numerous sauropod remains.

Moreover, this Tiguidi cliff should not be confused with the Cenomanian-Turonian cliff situated further south and forming the Damergou plateau, so remarkable for its development into a 250 km long circular arc. It is in reality determined by the “Tégama sandstone”, with which we parallel the In Abangarit series (fig. 5, section C).

The most eastern localities of Niger, situated in a hardly explored region, were discovered by Hughes Faure.
The EL RHAZ region (no. 12), a well whose name does not figure on official maps, is found some 150 km east-southeast of Agadès and around 25 km east of 9° longitude (fig. 9). It includes small sandy reliefs that are extended for 120 km from north-northeast to south-southwest; they belong to the “Tégama sandstone” sensu lato and show rather abundant vertebrate remains throughout their outcrop zone (distributions given by H. Faure).

Moreover, 110 km southeast of El Rhaz, the same geologist discovered in 1957 some varied bones and a large theropod tooth in an analogous horizon southwest of Egaro; the near-total absence of toponymy on the maps lead to grouping this locality with those of El Rhaz.

Another important fossiliferous region, discovered by H. Faure, is found on the eastern border of the Aïr, some 200 km northeast of Agadès and immediately south of the Takolokouzet massif. Some remains of the large Aoulef crocodile and some theropod vertebrae were found at three points (Tamat Tadent, Tagrezou, and Oued Baouet) in the Continental Intercalaire of the “Tefidet ditch” (locality no. 25). The sandy series with silicified wood is found here directly on the Precambrian of the Aïr [according to H. Faure, 1956; cf. M. Raulais, 1951]. Finally, in the course of his last voyage, H. Faure recovered a sauropod caudal vertebra in the full Ténéré.

According to M. Dalloni [1948, p. 31], some reptile bones were encountered at Toummo, in the north of the Djado. But the geologists who have passed there since (Lefranc and Freulon, B. R. P. mission) found nothing (cf. Bureau of Petroleum Research [1959]).

It could have been thought a priori that vertebrate remains could also be found in the great extents of the Continental Intercalaire that girdle the Tibesti. Having participated in the first Borkou-Ennedi-Tibesti mission of the A. E. F. Geological Service in 1954-1955, we were naturally attentive to the eventuality of such paleontological documents, more especially in the regions of Ounianga and the Erdis, where the Continental Intercalaire is widely exposed (fig. 1). But neither this mission, nor those of P. Vincent in the following years, found fossil fishes or reptiles there, the same in the zones where silicified wood of the Weichselia and Dadoxylon types are very abundant and confirm its parallel with the classic Continental Intercalaire [Wacrenier, 1958]. No bone having been noted in the Koufra region either, it would follow that the eastern Sahara seems rather poor in vertebrate localities, at least for the moment. Indeed the single locality of Baharija is cited there(fig. 2), which was very productive [Stromer, 1915-1934], but now seems exhausted according to J. Cuvillier (oral communication).1

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