2 THE FOSSIL ECHINOIDEA 



bearing rocks in Western Sind, others were derived from later tertiaries. None came 

 from the lowest series of rocks, the fossil Echinoidea of which form the subject of this 

 Part; but some were derived from the higher series, and will be noticed in the 

 description of their fossils. 



II. Origin of the Collections about to be described. 



After the completion of the description of the Fossil Corals of Western Sind *, the 

 Superintendent of the Geological Survey, H. B. Medlicott, Esq., F.R.S., decided to 

 accede to our request and to send to us for description the magnificent series of 

 Echinoidea which had been carefully collected by skilled collectors under the instruc- 

 tion of Messrs. W. T. Blanford, F.RS., the Deputy Superintendent, and Mr. Fedden, 

 F.G.S. 



The specimens we found to be numerous, usually in a good state of preservation, 

 and to have had their geographical and stratigraphical positions carefully recorded. 

 They had been obtained from all the fossiliferous horizons which had yielded fossil 

 corals to the Survey ; and, moreover, there was a collection included from the tertiaries 

 of Cutch. 



Anticipating that the examination of the Echinoidea might enable the geological 

 age of the upper members of the great tertiary series to be satisfactorily determined, 

 after the more or less definite statements which the study of the corals had necessitated, 

 we asked for and received a collection of fossils from the Makran series of Baluchistan 

 and the Persian Gulf. Lately a small collection of recent Echinoidea from the' coasts 

 of Sind has been sent. 



After considering the work before us, we agreed, with the sanction of the Superin- 

 tendent of the Geological Survey of India, to bring out the descriptions in Parts, each 

 of which will relate to the fossils of one of the great geological divisions. Every fossil 

 has passed a careful examination by both of us ; we have generally drawn the details 

 of the structures ; and many difficulties have been surmounted by a process of careful 

 mutual criticism. We have, where it has been possible, considered the varieties of 

 species and the variations during growth. 



III. The Stratigraphical Belations of the Deposits containing Echinoidea in 



Western Sind. 



The detailed description of the geology of Western Sind is to be found in the 

 Memoirs of the Geological Survey of India, vol. xvii. part 1 (1879), by W. T. Blanford, 

 F.E.S. &c., Deputy Superintendent of the Geological Survey of India; and it is 

 therefore only necessary to explain those parts of it which relate to the general succession 

 of the stratigraphical series and the position of the strata yielding Echinoidea. 



The mountain-ranges west of the Indus run nearly north and south, in irregular 



* "A Monograph on the Possil Corals and Alcyonaria of Sind," by P. Martin Duncan, Palssontologia 

 Indica, ser. xiv. vol. i. pt. 2 (1880). 



