Vol. 58.] ASSOCIATED BEDS OF THE MALVERN HILLS. JG: 
VII. Descrtprion oF THE HyoLitHIpm®, TRILOBITA, ETC. 
(a) Hyolithide. 
Theca (or Hyolithus) was recorded by Murchison from the Holly- 
bush Sandstone and Malvern Quartzite many years ago,’ and again 
from the Hollybush Sandstone by Prof. Lapworth.” But with the 
single exception of Serpulites fistula, Holl, hitherto not recognized 
as one of the Hyolithide, no specimens of Hyolithus from these 
beds appear to exist in the collections known to me. In the 
field specimens are very difficult to obtain, those collected being 
nearly all from débris in two localities where the rock is not 
exposed. They are, moreover, commonly in the condition of frag- 
mentary casts. Had it been likely that further material would be 
forthcoming, it would have been preferable to await the discovery 
of better specimens than those obtained; but since, owing to the 
practical exhaustion of the proper débris, this is not likely to occur 
for a long time to come, it has been thought advisable to describe 
the material already collected. 
Hyorrrats (OrtuorHeca) FistuLa (Holl). (Figs. 1-9, pp. 112-13.) 
The original specimens from which Serpulites fistula was de- 
scribed appear to have been lost, but examples presented by Holl 
may be seen in the Worcester Museum. The species is thus 
described by Holl* :— 
‘ Cylindrical, straight, tapering very gradually to a point; shell thin, smooth. 
Length 1 inch to 13 inch; diameter about 1 line.’ 
The fossil has all the appearance of being a Hyolithus. <A large 
number of specimens collected in the field enable me to give more 
precision to the foregoing definition. ‘Transverse sections vary from 
nearly circular to very broadly oval; occasionally, a slightly greater 
flattening on one side appears to indicate the dorsal surface. The 
largest specimens seen measure 2°5 mm. in diameter, and the 
smallest about 0°25 mm. Taking the smaller diameter as unity, 
the larger diameter varies from 1°05 to 1-28, the average of twelve 
examples giving 1-137 mm. ‘The angle of divergence of the sides 
commonly varies from 3° to 5°, but occasionally sinks below 1°. 
Fragments with a diameter of less than 0°5 mm., and possibly not 
belonging to Hyolithus fistula, show scarcely any taper*: thus a 
fragment 16 mm. in length (the longest seen) varies little from 
0-25 mm. in diameter. The shell is thin. The internal cast 
appears to be quite smooth, but the exterior of the shell is marked 
by closely-set, fine, transverse striz of growth. 
The operculum is probably represented by four incomplete 
1 ¢Siluria’ 4th ed. (1867) App. p. 541. 
2 Proc. Geol. Assoc. vol. xv (1898) p. 338. 
2 Quart. Journ. Geol. Soc. vol. xxi (1865) p. 102, 
* It is possible that some of these very slender fragments belong, either to 
‘oleoloides or to Hyolithellus. 
