440 Report of the Transactions of the Academy of 



theory of the formation of this rock, which will be read with 

 interest by all those who are disposed to extend the science of 

 o-eolowy beyond the mere observation of facts ; and to include 

 in it speculations tending to explain under what circumstances 

 the various rocks were formed. 



Dr. Harlan has read to the Academy five communications, 

 in which he describes several organic remains of considerable 

 interest. The first of these was a fragment found by Lewis 

 and Clarke near Soldier's Kiver, a tributary of the Mississippi. 

 This bone, which belongs to the valuable collection of the 

 American Philosophical Society, will constitute a new genus 

 amono- the Saurian rcptilia : it differs from the Ichthijosaiinis 

 and the other genera to which it is allied, by the circumstance 

 of the bodies of the teeth being in close contact, and by the 

 absence of the perforation which they present through the body 

 of the bone, offering a canal for the passage of the inferior 

 maxillary nerve. In Dr. Harlan's specimen there is a groove 

 running the whole length of the dental bone, immediately be- 

 neath the alveolar portion on the mesial aspect of the bone ; 

 from all which considerations, Dr. Harlan forms a new fossil 

 o-enus, under the name of Saurocephalus ; and from the lanci- 

 form nature of its teeth, distinguishes this species by the name 

 oi Saurocephalus lanciformis. 



By a reference to the collection of British fossils in the Phi- 

 ladelphia Museum, Dr. Harlan observed in it a specimen 

 which presents specific characters that have appeared to him 

 sufficient to distinguish it from those described by the Rev. 

 William D. Conybeare and other writers. He therefore de- 

 scribes it as a new species, under the name of Ichthyosaurus 

 coniformis. 



The many organic remains which exist in the tertiary for- 

 mations of New Jersey have attracted this author's attention, 

 and have given rise to a memoir " On an extinct species of 

 crocodile not before noticed, and some observations on the 

 o-eology of West Jersey." This paper contains some interesting 

 remarks upon what has been usually considered as a marl, hut 

 which the author is led to rank as a ferruginous clay, without 

 any claim to the tide of marl. In this clay many fossil reli- 

 quice have been found, such as Terebratula, Ostrea, Belemnites, 

 Ammonites, &c. also bones or teeth of sharks, crocodiles, tur- 

 tles, and a very remarkable tooth belonging to some Ichthyo- 

 saurian reptile, &c. In another communication upon the same 

 formation, the author notices three vertebrae belonging to some 

 Saurian reptile unlike any hitherto described, and the type of 

 which is not known to have existed in North America. One 

 of these was sufficiently well preserved to enable Dr. Harlan 



to 



