386 CARBONIFEROUS LAMELLIBRANCIIIATA. 



Black Mariue sliale, Woodball, AVater of Leith ; Newton and Knockbill Quarries, 

 Stratlikinness, St. Andrews; Di'umsLeugb, near Dean Bridge; zone 3 of Mr. 

 Kirkby, west of Pittenweera Harbour; all in the Calciferous Sandstone series 

 (Cement-stone group) of Scotland. 



Observations. — This species was described by Mr. R. Etlieridge, jun., in 1876, 

 under the name Leptodomus ? clavatiis, from crushed examples, and was redescribed 

 in 1878 by the same author as Pandora ? tijpica, the specific name being changed 

 because M'Coy had previously described a shell as Pandora ? clavata, ' Syuop. Carb. 

 Foss. Ireland,' p. 51, pi. xi, fig. 2. This time better preserved specimens were 

 figured. One of the specimens figured in Mr. R. Etheridge's original paper is 

 preserved in the Collection of the Geological Survey in the Science and Art 

 Museum, Edinburgh, and I refigure it PI. XL, fig. 7. It is crushed and has been 

 fractured obliquely along the ridge, making the shell appear as if carinated. The 

 figured types of Pandora ? typica are not in the same collection ; each of these 

 three specimens is stated to be in a private collection. In his remarks on the 

 species Mr. Btheridge says, " The reference to Pandora is made exclusively on 

 the close external resemblance this species bears to that genus. I have not seen 

 any of the internal characters, neither can I say whether the shell was inequivalve 

 or not, as it should be if a true Pandora.^' 1 doubt whether there exist any real 

 anatomical grounds for supposing that shells referable to the genus Pandora 

 existed in palgeozoic times. 



The figures of two species described by M'Coy have some resemblance to 

 S. clavatus, namely, Lutraria elongata and Pandora clavata. The type specimen 

 of the former is not in the Griffith Collection of the Science and Art Museum, and 

 I am unable to trace it. The type specimen of Pandora clavata is so poor as to 

 be quite undeterminable, and consequently Etheridge's original s|)ecific name has 

 been adopted, it being quite impossible to say to what genus Pandora clavata of 

 M'Coy belongs. 



>S'. clavatus has certain affinities with 8. aiigustatus, but it is much smaller, the 

 concentric ribs not so regular, and the posterior end is narrowed. This species 

 appears to be confined to the Calciferous Sandstone series in Scotland, and to be 

 one of the earliest, if not the first species of the genus in Carboniferous beds. 

 In England, however, it is present in the Redesdale Ironstone shales at a much 

 higher horizon. 



Mr. Kirkby {op. cit.), I think, confused the 8. clavatiis and 8. ahdenensis of 

 Mr. Etheridge. The latter is a smoother, more transverse shell, and is found in 

 a series of beds considerably higher than that in which 8. clavatus occurs : further 

 reasons for this opinion are given in my remarks on 8. abdenensis, p. 409. 



