FAUNAS OF AMEKICAX AXD SAILORS CAXYOXS. 397 



unquestionably would be placed in that system but for their association 

 with Amnionitinse. 



DaoneUa bdchiformis is a close representative of the D. bbchi, Mojsisovics. 

 which belongs in Europe to the passage beds between the Muschelkalk 

 and the Xoric series. The t3qDe of DaoneUa to which this and the follow- 

 ing species belong indicates the presence of the primitive forms of the 

 group of D. moussoni, as defined by Mojsisovics, which begins in the 

 Muschelkalk in Europe. There is also another form of DaoneUa asso- 

 ciated with the two mentioned here, but it is so close to D. bdchiformis that 

 for our present purpose it may be considered a variety of this species. 



DaoneUa cardinoides is a distinct species, but a close ally of D. bdchi- 

 formis, and therefore belongs to the same section of the genus. Speci- 

 mens of DaoneUa are found sporadically also in what must be considered 

 younger beds, containing compressed remains of Ammonitin^e, which 

 have presented a problem of a very interesting character. This was also 

 the geologic position assigned by Dr Lindgren and Dr Curtice, who first 

 collected them and studied the geology. At first sight the}^ appear by 

 their ornamentation to belong to the Lias. Unluckily the process of fos- 

 silization has entirely ol^literated the sutures, and the most careful and 

 repeated observations have failed to discover any traces of these parts. 

 The representation of external form and characteristics is so close between 

 some Ammonitinse of the Trias and Lower Jura that one cannot be sure 

 whether a given fossil occurs in the Upper Trias or Lower Jura unless 

 the sutures are present, with, of course, the exception of a certain list of 

 common and well known forms. It so happens that in this entire col- 

 lection there are but few which can be said to belong to this last men- 

 tioned class. 



Ammonites Bed. — The occurrence of what I have called Peronoceras (?) 

 americam.un at Sailors canyon and some other forms introduces a style of 

 ornamentation not yet found below the uppermost beds of the lower 

 Lias, but these fossils are not well enough preserved to be determinative. 



The Aptychi are of the bivalvular rugose type, and they would be 

 usually considered as supporting the opinion that these beds were not 

 older than the middle Lias and perhaps not older than upper Lias. 

 Nevertheless it must be remembered ihat a bivalvular Aptychus was 

 found in the Devonian of the Eifel and was described by D'Archiac and 

 De Verneuil,* and that a single Anaptychus also occurs in the Devonian, 

 both of them being associated with Goniatitinse. The argument there- 



* This Aptychus is bivalvular, but has a peculiar shape in that the valves are divaricated along the 

 median line and near the outer convex edge. Their internal e.lges, in other words, are not closely 

 approximate as in other bivalvular Aptychi. Tlie lines of growth are described as indistinct un- 

 dulating lines of growth, and the figure shows that it had a smoother surface than the rugose 

 Aptychi of the Jura to which the Sailors Canyon Aptychi can be closely compared. See Fossils of 

 the Older Deposits, etcetera, Trans, Geol. Soc. Lond., see. 2, vol. vi, pt. 2, pi. 26, fig. 9. 



