504 University of California Publications in Geology [Vol. 8 



TURRIS KIRKENSIS, n. sp. 

 Plate 69, figures 5, 6, and 7 



Shell small, elongate-ovate. Number of whorls five or six, which 

 are regularly convex, with obscure appressed sutures and acute apex. 

 Surface of shell sculptured by coarse, nodose, revolving ribs, between 

 which are finer and less nodose riblets. On each of the major ribs 

 there are about twenty rounded nodes; the nodes of the different ribs 

 are in line giving the shell the appearance of being longitudinally 

 ribbed. The distribution of the revolving ribs and riblets is as fol- 

 lows : Beginning at the suture on the body whorl there are two nodose 

 indistinct ribs below which are two of the finer unnodose riblets. the 

 anterior riblet being the heavier; anterior to this are two nodose ribs 

 with one fine indistinct unnodose riblet between. Between the last 

 two nodose ribs just mentioned and the anterior end of the canal there 

 are five of the major ribs between each of which excepting the last an- 

 terior two, there are two riblets, in each case the anterior of the riblets 

 is heavier and shows a tendency to be nodose. 



On some specimens toward the anterior end of the body whorl the 

 heavier of the two riblets seen between each of the major ribs becomes 

 as prominent as the major ribbing itself, the nodose character of the 

 ribs disappearing. Whorls of spire with three of the heavier nodose 

 revolving ribs; anteriorly at the suture are two of the riblets, the 

 heavier type of riblet being in front ; above these riblets are two of 

 the nodose ribs which are very close together with a faint indication 

 of an interrib between; posteriorly this is again followed by two 

 riblets the anterior one being the coarser ; above these is a nodose rib 

 between which and the suture is one of the coarser riblets. Posterior 

 sinus on specimens figured obscure ; outer lip sharp ; inner lip smooth, 

 incrusted ; canal short and straight ; umbilicus subperforate. 



Dimensions. — Type specimen: height, about 11 mm. ; greatest width 

 of body whorls, 5 mm. 



Occurrence. — In the Lower Division of the San Pablo Group, from 

 the region of Kirker Pass to the north of Mount Diablo, University 

 of California localities 102 and 40fi. 



