222 



the normal form. There are other specimens showing a simihir variation 

 and several are normal. The frontal apertnre varies from snlK-ireular to 

 a mere slit. 



The form of the spire varies from a fairly well-developed spiral cone 

 with flaring base and acute apex to a form approximating a disk with 

 verj^ obtuse apex. The most disk-lilvc form observed belongs to a shell 

 less ventricose than the average and rlie spire is turned from the normal 

 position. The number of whorls in the spires seems to vary slightly, 

 though the material at hand does not admit of certain determination m 

 this respect. Unfortunately the crural attachments of the spires are not 

 shown in any of the specimens. However they must have been somewhat 

 modified to accommodate the twisted position of the spires, unless, in 

 the specimens examined, the spires which are abnormal had broken loose 

 in the shell prior to fossilization. Avhich I believe is improbable. 



The above variations, except in the case cited, do not seem to accom- 

 pany any particular form of shell. There is nothing visible in the spec- 

 imens to show the cause of their abnormality. 



It is dangerous to generalize mucli on the observaliims based on a sin- 

 gle species. All that I suggest is tliat tlie foregoing seems to indicate 

 that in those spire-bearing brachiopods, pai'ticuhirly the Athyridae, where 

 the form of the shell does not govern the form and position of the spire, 

 i. e., those which approach a spherical form, the spiralia may be subject to 

 a considerable variation botli as to the form of the spire and its position. 



Topography and Geography of Bean Blossom Valley, Monroe 



County, Indiana. 



V. F. Marsters. 



In Monroe County, Indiana, and others lying to the southwest (Owen. 

 Greene, Martin, Dubois, Pike and Gibson) occiu' a number of preglacial 

 river vallej-s the present topography and content of which unmistakably 

 suggest the existence of a temporaiy period of laking. Inasmuch as the 

 attenuated edge of the Illinoian till plain passes diagonally through the 

 above counties and crosses the mouths of many of the southern tril)Utaries 

 to the west branch of "White Eiver, which present evidence of arrested 

 drainage near the limit of the till plain, it seems probable that the hiking 

 was consequently connected with the glaciation of the immediate region. 



