ORTHID. 213 
Moel Fodig ; Fridd-y-fedwen ; Mynydd Tryfan ; Cefn Barog; Fron-fawr; River Dee, south 
of Llangollen; Myndd-y-gaer. It has also been met with at May Hill, Usk, Rock Farm, 
Longhope; east of Cotwood, Whitfield, Tortworth, &c. In the Upper Llandovery at 
Llandovery ; Presteign ; Chirbury ; Wooltack; Bogmine; Norbury, Malverns, Huntley 
Hill, May Hill, Church Stretton, &c. &. In the Lower Llandovery at Ridge behind 
Penrock, at Cefn-Rhyddan, Mathyrafal and Pen-y-Craig, North Wales. In the Caradoc at 
Llanfyllin, Moelydd, near Llansaintfraid, Oswestry ; Llyn Idwal; Moel Siabod; Carnedd 
Dafydd, Bettws-y-coed, Dolwyddelan, Madryn Park (Carnarvonshire) ; Llanfwrog, near 
Ruthin (M‘Coy), Denbighshire, North of Llangedwyn; Meifod, Llanfyllin; Welshpool, 
Llanwddyn (Montgomeryshire). South of Llangollen, south and south-east of Cerrig-y- 
Druidion, Corwen; Llanrhaiaden; north of Tremadoc (Salter). Gretton, Shropshire, 
&e. &c. In the Upper Llandeilo at Tyn-Twr, four miles south of Llangefui, &c. 
In Scotland it occurs in the Wenlock Shales in the Pentland Hills near Edinburgh. 
In the Llandovery rocks at Mullock above Dalquorrhan, and in the Caradoc Limestone 
at Craig Head Quarry, Girvan, Ayrshire. 
In Ireland it has been found in many Upper and Lower Silurian localities in the 
- Counties of Galway, Kildare, Kerry, Mayo, Wexford, Waterford, Wicklow. It has been 
obtained at the Chair of Kildare, Kilbride, Cong, Egool, Ballaghaderreen, Tramore, Black- 
water, Leenane ; Holyford, County Tipperary, &e. 
Abroad it is very common in the Island of Gothland; has also been found in the 
Silurian rocks of Russia, Bohemia, United States, &e. &c. 
Ortuts crassa, Lindstrém. Pl. XXVII, figs. 17—19. 
Orvuts crassa, Lindstrém. Gotlands Brachiopoder, p. 369, 1860. 
Spec. Char. Shell almost circular, sometimes transversely oval, widest about the 
middle ; hinge-line shorter than width of shell; both valves convex, sometimes gibbous, 
the ventral one always most so, while a mesial depression extends from the umbone to 
the front in the dorsal one. In the ventral valve the beak is small and much incurved, 
so that the beaks of both valves. are often very approximate ; areas narrow; surface 
of both valves covered with numerous small radiating ribs, which increase in 
number by bifurcation as well as by the interpolation of small ribs near the 
margin. ‘The valves are also marked by concentric lines of growth. ‘Two specimens 
measured— 
Length 6, width 6, depth 5 lines. 
nw) Gupteol Salastiee eis 
Oés. Dr. Lindstrém informs me that this species differs from O. e/egantula, to which 
