76 



in connexion with the lithological characters, and stratigra- 

 phical position of the rock in which they occur, we think 

 there is scarcely room to doubt that it is of Permian age. 



This formation will probably be found to have a consider- 

 able geographical distribution in the far west, perhaps in 

 the form of isolated beds, when attention is called to it ; at 

 any rate, in addition to the locality from which Major 

 Hawn collected his specimens near the mouth of Smoky 

 Hill fork of Kansas river, Dr. Cooper collected some of the 

 same fossils near Helena, about one hundred miles in a right 

 line north-east of that, and as already stated, we have, for a 

 long time past, had a few of the same fossils from a locality 

 on the Missouri, in Nebraska, opposite the northern boun- 

 dary of Missouri. 



Much credit is due Major Hawn for his zeal and industry 

 in developing the geology of Kansas. He informs us he 

 contemplates publishing soon, a work designed for popular 

 reading, on the agricultural and other natural resources of 

 that territory, which will doubtless contain much useful and 

 interesting information to those who may wish to know more 

 in regard to this new, and much talked of country. 



DESCRIPTIONS OF THE NEW FOSSILS. 

 Monotis Hawni. 

 Shell subcircular, very slightly oblique; beaks located a 

 little in advance of the middle ; hinge line straight and 

 equaling about half the length of the shell. Larger valve 

 convex; beak usually extending little above the hinge 

 apparently not very much incurved, anterior margin, more 

 or less rounded, sometimes faintly sinuous just below the 

 extremity of the hinge, so as to form a very small indistinct 

 obtuse ear, but more frequently rounding rather abruptly 

 into the hinge, so as scarcely to leave any anterior auricu- 

 lar appendage ; basal and postero-basal margins rounded ; 



