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AMERICAN JOURNAL 



sidered formerly a var. of Dupetithouarsi,* Mr. Rowell also 

 found Triod. loricata near this place, but at Placerville I could 

 not discover a trace of Helicoids. In Placer Co. this limestone 

 is mostly covered by basaltic rocks, but reappears in Nevada 

 Co. at "Lime Kiln," ten miles south of Grass Valley, near lat. 

 39°. In this vicinity Mr. Voy found the dwarfed specimens of 

 H. tudicidata before mentioned, at an elevation of near 3000 

 feet. I had before found a few at Auburn, twenty miles south- 

 west of there, but not on a limestone belt, though near the pre- 

 ceding one. 



Apparently the same limestone belt reappears at Pence's 

 Ranch, nine miles north of Oroville, and 1000 feet above the 

 sea, but the Survey collectors did not bring any Helicoids from 

 that celebrated locality, where this carboniferous limestone runs 

 beneath the cretaceous strata rich in fossils. It continues cov- 

 ered for ninety miles, and then reappears at "Bass' Ranch," 

 just at the junction of the Sacramento and Pit rivers, about 

 1200 feet above the sea. Here Prof. Brewer found Mormonum 

 abundant, but chiefly dead specimens, and this seems to be its 

 most northern and western locality, 290 miles north-west of 

 where it was found by Mr. Gabb in Fresno Co. ; Dr. Newcomb, 

 however, gives also Klamath Co, (Voy). Like all the species of 

 wide range, it has several marked varieties in size and color, but 

 retains its form and number of whorls throughout with marked 

 tenacity. Some specimens are subangled, approaching Hille- 

 brtindi, and others southward very large, the whorls swollen, and 

 perhaps the form intended by Thomson's "H. cultellata." Better 

 specimens may prove, therefore, to be a distinct species. 



A short outcrop of limestone occurs at Genesee Valley, sixty 

 miles north-east of Pence's Ranch, at about 4500 feet elevation, 

 but no large Helicoids are known to have been found there, or 

 elsewhere in the north eastern portion of California, which is 

 nearly all covered by basaltic rock. Hyalina Breweri was found 

 by Prof. Brewer at some unknown point in that direction, and 

 only one specimen brought. 



Patula Oronkhitei, Newc, was discovered just north of the 

 Californian boundary by Dr. Cronkhite, U. S. A.,f near the 

 shores of Klamath Lake, 4000 to 5000 feet above the sea, and 

 found also in some part of northern California by Mr. Voy. The 



* Specimens from the scantily wooded localities are often palest be- 

 neath, and vice versa. 



f This is a mistake, /obtained the species as stated, and, believing it 

 to be new, I handed specimens to Dr. Newcomb with the MSS. name, 

 which the latter adopted for his description. W. M. G. 



