RHYNCHONELLID Al. 183 
Upper Ludlow rocks ; and the obtuse-looking examples (nwcu/a) often prove, on counting, 
to have the same number of ridges, and to have the same proportions as the sharply 
marked ones (pulchra).’ T. pulchra is therefore added to the synonyms by Prof. M‘Coy, 
and where it may also for the present be allowed to remain, and especially so since it is 
entirely ignored in ‘ Siluria.’ Again, Mr. Salter informed me, when I met him last in 
Cambridge, that 7. pusilla, Sow., from the Lower Llandovery rocks of Cefn Rhyddan, 
was nothing more than a small specimen of RA. nucula; and I must confess that the 
inspection of the crushed valve on which Sowerby founded this so-termed species would 
lead me to agree with Mr. Salter. It is stated to be “nearly globose, plaited, plaits 
about 14, sharp, 4 of them elevated in the front; length and width nearly 4 lines,” a 
description which will well suit RA. nucula. Lastly, in page 545 of the 2nd ed. of 
‘Siluria’ we find a Rhynchonella from Worcester Beacon, Upper Llandovery, identified 
by Mr. Salter as the 2A. obtusiplicata of Hall (‘ Pal. New York,’ vol. ii, p. 279); but 
upon examining the imperfect specimen or specimens upon which this identification is 
founded, and which is preserved in the Museum of Practical Geology, I am strongly 
impressed with the idea that it also must be referred to Rh. nucula ; its ribs are angular, 
not rounded, and of the fourteen ribs which may be counted on the dorsal valve 
four occupy the fold. A figure of this specimen will also be found in Pl. XXIV, fig. 7. 
Although the usual number of ribs in the fold of RA. xucula is four, sometimes there 
are but three, and some specimens have presented as many as five. 
Position and Locality. If all the shells here referred to RA. nucula do in reality belong 
to the species, its range would be considerable, for we should have it in the Lower 
Llandovery, Upper Llandovery, Woolhope Limestone, Wenlock Limestone and Shales, Lower 
and Upper Ludlow, and Aymestry Limestone. A vast number of localities have been named 
in various works, but I cannot answer as to the correctness of them all, any more than of 
some of those I have transcribed from different works relative to the other species described 
inthis work. The larger number of those I am about to name are taken from vols. ii and 
iii of the ‘Memoirs of the Geol. Survey,’ as well as from the lists in the possession 
of the Geol. Survey. Many more could be given, but those here recorded may, I 
think, suffice. 
Upper Ludlow—Overley, Hope End Park, Malvern district ; west of Rock Farm, May 
Mill district ; Usk ; Aberedw and Cwm Craig ddu, Builth district ; north-east of Pillard’s 
Barn, Woolhope ; Nun Hill, Cleobury, Kington, Hereford ; Frith Farm, and Horeb Chapel ; 
Burton and Brokton, near Wenlock ; Collinfield and Benson Knot, Westmoreland ; Down- 
ton Castle, Aymestry, Herefordshire ; Woolhope, &c. 
Aymestry Limestone—Rilbury, Malvern district ; Backbury Camp, Woolhope district ; 
Llanbadock and Ty-Newydd, Usk district ; Shucknall Hill, Woolhope district ; Sedgley, 
near Wenlock, &c. 
Lower Ludlow—South of Putley, Woolhope district ; Pyrton Passage; Leintwardine, 
Shropshire, &c. 
