CRETACEOUS STRATA OF THE LOWER XARBADA REGIOX. 



151 



1884, by P. X. Bose, B.Sc. (Lond.), F.G.S. Mr. Bose collected 

 fossils in abundance, from the Modular limestone, the Argillaceous 

 limestone or marl, and also from the Coralline limestone. He found 

 an Ostrea-hed. on the top of the sandstone mentioned by Blan- 

 ford, and his palaeontological researches and stratigraphical results 

 led him to adopt the following views : — 



The age of the Sandstone is not settled, but the Ostrea on the top 

 he believes to be 0. Leymerii, d'Orb. ; it is Neocomian in Europe. 

 The Nodular limestone rests conformably upon the Ostrea-'bedi and the 

 Sandstone, and some of the same Ostrece are found in diminishing 

 numbers in it. The Modular strata Mr. Bose assigns to the Gault in 

 one part of his work, and to the Albian and part of the Cenomanian 

 in another. The Argillaceous limestone rests conformably upon the 

 Nodular series, and contains the species formerly described in Quart. 

 Journ. Geol. Soc. 1865, which were collected by Captain Keatinge. 

 To this horizon Mr. Bose gives the correct names of Cenomanian 

 with part Turonian. The Coralline limestone rests upon the Argil- 

 laceous limestone conformably, and after an examination of its 

 fauna, Mr. Bose decides that it is Senonian in age. Mr. Bose, I 

 regret to state, writes about the determinations of the species having 

 been made by him " roughly ; " and it became evident, after studying 

 his memoir, that there were not sufficient grounds for believing that 

 the whole Cretaceous formation was represented in about 80 feet 

 of conformable strata, the whole of the series from the Gault or 

 Albian, to the Senonian inclusive, following conformably upon a 

 Keocomian. 



As Mr. Bose recognized some of the Echinoidea I had noticed, 

 and as there was a good collection made from all the horizons, ex- 

 cept the so-called Neocomian, I applied to Mr. Medlicott for the loan 

 of the Echinoidea, with a view of describing them in the Becords of 

 the Geological Survey of India. Mr. Medlicott sent me the collection, 

 as also one made by Mr. Blanford many years before, and that 

 of Captain Keatinge, which had been placed in the Museum at 

 Calcutta. The fossils in the Museum at Calcutta which had been 

 collected many years ago by Captain Keatinge, came from the 

 Argillaceous limestone or marl, and therefore were from the same 

 strata as those which had been studied by me in 1865. Unfortunately 

 this little group of well-preserved specimens was not studied by the 

 last surveyor of the Cretaceous rocks, nor does it appear that he 

 made himself acquainted with the forms which had been collected 

 by Mr. Blanford. But Mr. Bose found some species in the collection 

 which he made, and which I had not seen in the marl. In order to 

 arrive at the truth with regard to the Echinoidea, I re-examined 

 the collection in the Museum of this Society, and found that only 

 one species required further consideration. It appeared to me that 

 although the general shape of the Echinobrissus warranted the 

 specific name I had given it, the details of the ambulacra were 

 insufficiently seen. These details are well shown on a specimen 

 which Mr. Bose obtained from the same horizon, and there is no 

 difficulty in recognizing the petaloid condition of the posterolateral 



