154 



BRITISH SILURIAN BRACHIOPODA. 



he could not have had an opportunity of comparing a perfect example of it with the 

 complete specimens of P. ohlongus figured by him in the same plate. 



Position and Locality. Pentamerus ohlongus would appear to be restricted to the 

 Lower and Upper Llandovery rocks, and to be very much more abundant in the last- 

 named formation. At page 229 of ' Siluria,' (2nd ed., 1859), it is stated that, "In the 

 Lower Llandovery rocks of South Wales P. undatus and P. lens are everywhere found, 

 P. glohosus and P. ohlongus being rare. In the upper series, whether in South 

 Wales, Shropshire, or in the South of Scotland (as at Saugh Hill, near Girvan), P. ohlongus 

 is the prevailing fossil, occurring often in great banks, to the exclusion of all other 

 fossils, but generally accompanied by the species just named. At May Hill and the 

 Malverns P. lens is by far the more common species; P. liratus accompanies both these 

 in the higher beds, and is the only one of the five species which ranges into the base of 

 the Wenlock formation." Among the English and Welsh Lower Llandovery localities 

 may be named Cyrn-y-brain, Wrexham, Denbighshire ; Cefn, three miles north-east of 

 Welshpool, near Buttington ; also near Builth, and at Noedd-Grug and Llandovery, 

 rare (J. W. S.). In the Upper Llandovery, Nash Scar (Presteign) ; Norbury, Bishops 

 Castle, Stone Acton, Church Stretton, Chirbury, Hope Bowlder, and the Hollies, in 

 Shropshire ■} Pen Cerrig, Builth ; Llangadoc ; Wooltack Park, Pembrokeshire ; Rose 

 Market, near Haverfordwest, and Johnston ; Pen-y-lan ; Old Storridge, near Malvern. 



Prof. M'Coy mentions Pwllheli, Carnarvonshire, and some other localities, giving 

 the " Upper Bala sandstone " and " Caradoc sandstone and limestone," such as that of 

 Soudley and Horderley, Shropshire: in all these the May Hill sandstone is meant 

 (J. W. S.). 



At p. 292 of the 2nd vol., part 1, of the 'Memoirs of the Geol. Survey of Great 

 Britain,' Messrs. Phillips and Salter mention Fair Oaks, Gunwick Mill, and Howler's 

 Heath, Malvern district ; Ankerdine Hill, Abherley district ; May Hill, and Huntley, May 

 Hill district ; Mandinam, Llandeilo district. 



In Scotland, it abounds in the Yellow Llandovery Sandstone of Saugh Hill and 

 Penwhapple Glen, the conglomerates of Cuddystone Glen, and the blue limestone of 

 Ardmillan and Penkill, near Girvan, Ayrshire. These are Upper Llandovery (Salter). 



In Ireland, it is stated by Prof. M'Coy, in his 'Synopsis of Silurian Fossils,' to occur 

 in the (Llandovery) sandstone of Boocaun, Cong, Co. Galway (very abundant in one bed), 

 and in the sandstone of Cappacorcogue, Cong. A fine valve from this place will be 

 found figured in our plate. Mr. Salter found it on the precipices west of Dingle ; and it 

 occurs in the Lower Old Red conglomerates of that wild district, washed out in Devonian 

 times from the May Hill rocks (J. W. S.). 



Abroad, P. ohlongus is equally abundant. In Russia Prof. P. Schmidt mentions 



1 Tl>e masses of blue limestone full of the broad-arrow-like sections of the shell are the 

 " Jacobsfonea" of Shropshire. The line of the formation may be traced by the door-sills and Mell-steps 

 'if the cottagers. 



