144 Geological Society. 



A paper by Mr. Cunningham describes the physical structure, and 

 to a certain extent, the geological composition of the country be- 

 tween Hunter's River and Moreton Bay, in Australia, and is accom- 

 panied by a valuable map and section and a small collection of rock 

 specimens. The additions made during the expedition referred to 

 by Mr. Cunningham are important, and the geological notices, 

 though slight, will be welcomed by future inquirers. 



Mr. Rogers, who laid before the British Association at Edinburgh 

 an able sketch of the " Geology of North America," has more re- 

 cently favoured this Society with an account of the strata situate on 

 the banks of the Missouri and Mississippi rivers, and further, in the 

 district of the Rocky Mountains. It may be said of all these papers 

 that they are in a great degree compilations, but compilations so ex- 

 ecuted are perhaps among the most valuable documents that can be 

 transmitted to us. No general views could ever be opened if every 

 author were to confine his descriptions and reasonings to those 

 minute tracts which have fallen within the sphere of his own per- 

 sonal examination. Every system and theory is necessarily founded 

 upon details industriously collected from various quarters. 



Besides these communications, we have received from America 

 recently two works, in which the same subject is treated with great 

 clearness and in considerable detail: the one entitled " Contribu- 

 tions to Geology, by Isaac Lea, accompanied by six plates of 

 Shells," of which some at least are not very accurately figured ; 

 the other " A Synopsis of the Organic Remains of the Cretaceous 

 Rock, with nineteen lithographed plates of Shells, by Dr. Morton." 

 These works, together with the papers of Mr. Conrad published 

 previously in the American Journal of Science and the Journal of 

 the Academy of Natural Sciences of Philadelphia, illustrated also 

 with lithographic plates, have rendered the upper formations of 

 the United States as intelligible as those of our own country. 



Dr. Morton notes the generic accordance of the Testaceous Mol- 

 lusca on the east and west shores of the Atlantic; but indepen- 

 dently of genera, there are at least twenty-four species common 

 to both. In like manner some identities have been traced in 

 the tertiary deposits of Europe and America. The Pecten quin- 

 quecostatus in particular occurs equally in the cretaceous group on 

 both sides the Atlantic; nor is the analogy confined toTestacea -, it 

 extends to the Saurian reptiles. The animals whose remains are 

 found in chalk formerly inhabited the seas of the two continents, 

 and whatever cause bared the eastern, appears to have acted simul- 

 taneously on the western mass; not a rush of currents, but a subsi- 

 dence or elevation. 



In the county of Onondago, in New York, is a lacustrine depo- 

 sit still forming, in which thousands of tons might be obtained of 

 bleached shells. The shells at the mouth of the Potomac river, be- 

 longing to the newer Pliocene beds, retain their colours ; twenty- 

 nine of the species are the same with those which now live, and of 

 these there are seven only which are not known to inhabit the coast 

 of America. 



