594 PROCEEDINGS OF BOSTON MEETING. 



The following paper was read by title : 



RELATIONS OF SYNCLINES OF DEPOSITION TO ANCIENT SHORELINES 



BY BAILEY WILLIS 



An abstract of this paper is published in The American Geologist, 

 volume xiii, February, 1894, page 140. 



The next communication was : 



THE LATER TERTIARY LACUSTRINE FORMATIONS OF THE WEST 



BY W. B. SCOTT 



I Abstract] 



The uppermost of these horizons in the western interior region has been called 

 the Equus beds, which in many places overly the Loup Fork beds and have not 

 always been distinguished from them with sufficient accuracy. Hatcher has shown, 

 however, that the two are separated by a marked unconformity, and there are 

 notable lithologic differences also. The mammalian fauna of the Equus beds, while 

 abundant in individuals, is scanty in species, which, for the most part, belong to 

 modern genera, such as Equus, Elephas, etcetera, together with a few extinct genera, 

 as, for example, Mylodon, Eschatius, etcetera. Rhinoceroses, which are so conspicu- 

 ously represented throughout the undoubted Tertiaries of North America, have not 

 been found in the Equus beds, except, perhaps, in California, where they appear 

 to have lingered later than elsewdiere. The character of this fauna points rather to 

 a Pleistocene than a Pliocene age of the beds. 



The Blanco of Texas, described by Cope, is a typical Pliocene, the only beds so 

 far identified in the West of which such an age can be certainly predicated. They 

 precede somewhat the Peace Creek beds in Florida, which Dall has found inter- 

 stratified between marine Pliocene beds. 



The great Loup Fork formation has been much misunderstood, partly because it 

 has not always been distinguished from the much later Equus beds, and partly be- 

 cause the separate horizons into which it may be divided have but lately been 

 worked out. Of these there are three. The oldest is the Peep River horizon of 

 Montana [Ticholeptus bed of Cope) and is characterized especially by a number of 

 aberrant oreodonts and some i)eculiar genera of horses, such as Desmatlppus and 

 Ancldtherimn. This hoi"izon is so far known only in Montana. I cannot agree with 

 Cope in referring to it certain deposits in Wyoming and Oregon. 



The second or middle horizon of the Loup Fork covers a vast area from Nebraska 

 to Mexico, and has yielded a very large number of mammals. Of these the most 

 characteristic is, perhaps, the antelope-like genus Cosoryx. An appropriate geo- 

 graphic name for this subdivision would be the Nebraska. 



The latest of the three horizons of the Loup Fork may be called the Palo Duro, 

 Cope having found it near the canyon of that name in Texas, and Hatcher has 

 observed it in northern Kansas overlying the Nebraska series. The horizon is 

 characterized by the first appearance of the genera Equus and HippkUum, while 

 Proioh'vppas and Aplielops continue up from the Nebraska or Loup Fork proper. 



The mammalian fauna which has been found at and near Archer, in Florida, 



