402 a. hyatt — trias and jura in the western states. 



Upper Jura in California. 



ammonitin^. 



Cardioceras dubium. — One lot of fossils from Texas ranch, Calaveras 

 county, collected by Dr G. F. Becker, is largely composed of Ammonitinse 

 of one species, described below as Qardioceras dabmm, and is found asso- 

 ciated with Aucellse. The sutures are present, and although much dis- 

 torted, give indications of affinity of considerable value. The evidence 

 shows that it is a species of Cardioceras and that the age of the slates in 

 which it occurs is Upper Jurassic. The nearest affine or representative 

 of this is a peculiar variety of Cardioceras alternans, sp. Von Buch, which 

 is found in the Oxfordian and only in the Russian fauna, and is there 

 also accompanied by the first representative in that region of the genus 

 Aucella. 



Perisphinctes virgidatiformis. — Perisphinctes virgulatiformis was found by 

 Dr Curtice near Reynolds ferry, Stanislaus river, opposite Bostwicks bar.* 

 This species has all the peculiar external features and the sutures also of 

 a characteristic series, the Virgulatus group of this genus, which occurs 

 only in the Upper Jura in Europe. The nearest affine is a species from 

 the Solenhofen slates, described by Quenstedt as Aiiwionites planulatus 

 silicius. 



CEcotraustes denticidata. — (Ecotraustes denticulata was also found at Rey- 

 nolds ferry by Dr Curtice, and this is a member of the smooth-whorled 

 section of the genus, having a denticulated keel. It is allied to CEco- 

 traustes lochensis, sp. Oppel. of the Oxfordian, and, like the preceding, indi- 

 cates the Upper Jura. 



Associated Forms. — Associated with these Ammonitinse at Reynolds 

 ferry there are some species of Cerithiiiin, of no great value in determin- 

 ing the age of the rocks ; also some Pelecypoda, too imperfect to be of use. 

 There is also from this locality an Aviculoid, which may be a near ally of 

 the peculiar shell first described as Aucella impress^, Quenstedt, from 

 Upper Jura of Wurtemburg. Unluckily I have not been able to deter- 

 mine whether the best specimen had an anterior ear like the shell de- 

 scribed by Quenstedt or whether the mark I saw was part of a tooth. 

 This so-called Aucella impress^ of Quenstedt, as stated by Lahusen, is 

 certainly not a true Aucella^ nor even a member of that genus. 



Peinsphinctes jiliplex (?). — Perisphinctes filiplex (?) sp., Quenstedt, found 

 on the south bank of Tuolumne river at Moffats bridge, on the Stanislaus 

 river near canyon opposite the mouth of Bear creek and six miles from 



*A"bai'" is a term used in the west to indicate a locality on a river where placer mining is 

 carried on. 



