[WILLIAMS] FOSSIL FAUNAS OF THE ST. HELEN'S BRECCL4S 233 



28. Rensselœria cf. muiahilis, Hall. 



A specimen somewhat larger tlian any of Hall's figures and having 

 more numerous striœ is referred to this species. It is distorted by 

 crushing but the size of the specimen is 13 mm. wide by 14.5 mm. long. 

 It is apparently intermediate between R. mutabilis and R. œquiradiafa 

 in respect of .size of plications, but it is quite too small to be referred 

 to an adult of R. œquiradiata. Two other smaller specimens present 

 more (cHosely tJie f^izc and form of /'. mntabilis. They probably are re- 

 presentatives of the same species which is here listed as probably equi- 

 valent to R. mutabilis. 



■ 29. Platyceras cf. clavatum. Hall. 



A small specimen of Plat3Teras has a restriction on the side beyond 

 which the shell suddenly expands, as in P. clavatum. I refer it to this 

 species but with no intent of accepting the view that the differences by 

 which most species of the genus Platyceras are distinguished are of 

 more than varietal or often accidental value. 



FAUXA OF LOT 252.3. 



The following species come from the original lot 3 (252.3) separ- 

 ated by the dyke from lot 2 (252.2). 



1. Favosites lielderhergiœ, Hall. 



Several masses of this coral are seen in the material from locality 3. 



2. cf. Lichcnalia dislans, Hall. 



A fragment of the celluliferous surface of a frond (see Pal. X. Y. 

 A^ol. VI, 1887, PI. XV, Figs. 8, 9), shows the pores six or seven in the 

 distance of 2 mm., separated from each other l)y smooth space al)out 

 equal to the diameter of each pore. The substance of the coral is 

 partially dissolved and the pores do not show the elevated rims described. 

 No structure except the flattened disc with perforations is evident. 



3. Orthis multistriata, Hall. 



Two specimens of normal size and markings occur in this lot, 

 agreeing in their characters with the species as found abundantly in the 

 lot 2, the other side of the dyke. 



4. Strophcodonta arata. Hall. 



A single specimein of medium size (19 x lli/o min.) shows the 

 characteristic form and markings of this species. This is also abundant 

 in the exposure the other side of the dyke. 



