236 EEPOET UNITED STATES GEOLOGICAL SUEVlIY. 



24. Tellina? modesta Meek. 

 See remarks under No. 22. 



25. Tellina (Areopagia) utaliensis Meek, 

 See remarks under No. 22. 



26. Gorhula nematopliora Meek. 



Meek reports the type specimens of this species from Southern Utah. 

 I figured an example from that region in vol. iv, U. S. Expl. and Sux. 

 West of the lOOth Meridian, which is probably of this species. The 

 examples that I have referred to at CoalviUe were found associated with 

 true marine, and not brackish-water, forms ; as is also the following 

 species. A figure of Mr. Meek's type is also given in another part of 

 this volume. 



27. Gorhula duMosa White. 



Found also in the valleys of Bear Eiver and Sulphur Creek. See notes 

 (m Cretaceous fossils of Bear Eiver Yalley. 



28. Martesia f 



Too imperfect for specific determination. 



29. Melampus antiqmis Meek. 



In No. 16 of Mr. Meek's section, which he found exposed in Carleton's 

 coal-mine about two miles southwestward fr^om Coalville, he discovered 

 a very interesting group of fossils, being Nos. 12, 17, 21, 29, 30, 32, 35, 

 36, 46, 47, and 49 of the foregoing list. Soon after his visit there the 

 mine was abandoned and the fallen debris has so obscured the strata that 

 no further collections fr'om them have ever been made. Neither has any 

 discovery of this deposit ever been made in the neighborhood or else- 

 where, although one or two of the species have been doubtfully identi- 

 fied from Cretaceous strata elsewhere in Utah. Two of these eleven spe- 

 cies of moUusks, Nos. 29 and 30, are palustral or littoral pulmonat^s ; 

 two, Nos. 17 and 49, are fi-esh-water branchifers ; four, Nos. 21, 32, 35, 

 and 36 are brackish- water forms, and the remaining three species, Nas. 

 12, 46, and 47, may be regarded as marine forms. To the latter may be 

 added a Cardium, mentioned by Mr. Meek, but not enumerated in the 

 foregoing list ; and to either the brackish or marine forms may be added 

 the Anomia^ also mentioned by Mr. Meek as occurring with the others. 

 This last-named species may be identical with the one found by myself 

 in the sandstones of the second ridge and mentioned under the head of 

 No. 6 ; but it is probably not the same. 



This mixture of palustral, fresh- and brackish- water and marine mol- 

 lusks may be taken to indicate an estuary origin of the strata containing 

 them, although a somewhat similar admixture is found in a large pai't 

 of the Laramie Grouj), extending over an area so wide as to make it 

 certain that these deposits at least were made in a large, brackish- water 

 sea. However, the evidently limited extent of this Coalville deposit, and 

 the presence in it of so large a proiiortion of marine forms, may be re- 

 garded as almost certainly indicating its true estuary origin. Tliis "view 

 is also supported by the evidence that a western shore-line to the Cre- 

 taceous sea existed not far distant from this locality. The Physa, No. 31 

 of the list, was found among the marine forms of the sandstones of the 

 second ridge of Mr. Meek's section. This also indicates a then neighbor- 

 ing shore-line, but not necessarily an estuary ; but the presence of brack- 

 ish- and fresh- water brauchiferous mollusks, as in No. 16 of that section, 

 seems to plainly indicate an estuary origin of the strata containing them. 

 These last-named moUusks, as weU as their pulmouate associates, are 



