OF AN EOCENE SIRENIAN MAMMAL. 103 



position that the carcass of a dead Sea-cow should be caught by a 

 current and carried very far out to sea before it sank and became 

 imbedded. 



That more of the skeleton of this Sirenian should not have been 

 recovered is due to the entire absence of any care or attention to such 

 appearances on the part of the native workmen, who break up the 

 matrix into small pieces for their modern rubbly method of construc- 

 tion. The happy accident of Dr. Grant's attention being attracted to 

 one of these bits led to the acquisition of the subject of the present 

 communication. My own repeated search of the quarries and quar- 

 ried material was repaid by the acquisition of other fossils not before 

 noticed, and which I may at another Meeting bring before the Society. 

 My friend Dr. Grant has promised to transmit any teeth or portions 

 of bone in the same stone which may appear to have belonged to the 

 animal or species to which I refer the natural model of the brain. 



The fine-grained white calcareous stone, quarried of old to an 

 enormous extent from Mokattam to Toorah (some of the old detached 

 colossal blocks being picked at, as it seems, by a race of pygmies, 

 comparatively, at the present day), overlies the strata forming the 

 base of the cliff, of yellowish limestone, containing fossils of Callia- 

 nassa, Nerita conoidea, Periaster obesus, Alveolina oblonga, Nummu- 

 lites planulatus, &c. 



With the Eotlierium were associated Conoclypeus Memmingii, 

 Nautilus Labechii, D'Arch., Nautilus Forbesii, D'Arch., fine casts of 

 Cerithium giganteum, of Turbo, of Rostellaria, of Cyprina ; not a 

 few of my fossils are well-preserved specimens oiLobocarcinus, nearly 

 allied to, if not identical with, L. Paulino- Wurtemburgensis, Reuss 

 and von Meyer, — all testifying to the Eocene period of its deposition. 



This white calcareous zone, of immense thickness at some parts, 

 is overlain by Miocene strata, with Clypeaster cegyptiacus, Pecten 

 aduncus, teeth of Carcharodon, numerous Ostrece and Placunaz. From 

 these deposits have been derived the far-scattered petrified wood, 

 from my gatherings of which Mr. Carruthers has determined two 

 species of Nicolia *. 



The exposed surface of these strata presents a reddish tinge. A 

 detached, outlying mass, on the way to the " petrified forest," takes 

 its name " Jebel Achmar " (red hill) from the red quartzose material 

 which predominates therein. 



The Sirenians present so singular and extreme modifications of 

 the mammalian type that one is specially moved to ascertain at what 

 period it was first manifested. I regret that I have not been able 

 to obtain evidences of the geological zone or age of the " red con- 

 glomerate and sandstone forming the river-course " near " Freeman's 

 Hall, Jamaica," where the fossil skull of, to my knowledge, the least- 

 modified of Sirenian forms was obtained f . All that I could learn from 

 its discoverer was that this river-bed was " overlain by limestone, dif- 

 fering from the general Tertiary carious limestone of the island " %. 



Eotherium, as exemplified by the brain-cast, is of Eocene age, of 



* Geological Magazine, vol. vii. p. 306 (1870). 



t Proceedings of the Geological Society, June 13, 1855, p. 511. J Ibid, 



