230 



SrPPLEMENT TO THE 



Geneka and Species. 



. 



1 

 I 



^ 



1 



3 



1 



1 



c 



3 



Localities. 









1 



Black Burn, LcaclhlU District, Dumfriesshire; Snar Water,' 

 Lanarkshire. 



Black Burn, Wanlock Water, Dumfriesshire. 



Bed D, North Esk, Pentland Hills, Midlothian. 



Kilbucho. Peehleshire; Snar Water, Lanarkshire; East Bay, 

 Gipsy Point, Kircudhrightshire ; East Burn, Lauder, Berwick- 

 shire; Dantercleugh Burn, Dumfriesshire. 



Duntercleugh Burn, Wanlock Water, Dumfriesshire. 



Duntercleiigh Hum, Dumfriesshire ; KWhucho, Peeblesshire ; Snar 

 Water and Glentrip Burn, Lanarkshire. 



Bed D, North Esk, and in thin limestone Gutterford Burn, Pent- 

 land Hills, Midlothian. 



49 — corrugatellii, 7)af 









50 Leptjena transversalis, JFahl. 



X 







51 — scricea. Sow. 







I 





52 — scricea, var. rhombica, 

 M'Coy 









53 — tenuicincta, M'Coy 









54 CnoNETES striatclla, Dal. 



X 

















If we briefly consider the general results shown by our Tables of Scottish Silurian 

 Brachiopoda, it will be seen that about 134 so-termed species have been discovered and 

 distributed into 25 genera; that about — 



C4 species are recorded from the Llandeilo formation (including much of the Loiccr 

 Caradoc of Murchison, Ramsay, and Gickie). 



44 from the Lower, Middle, and Upper Caradoc (including beds from a little below 

 the Caradoc Limestone of North Wales to the base of the Lower Llandovery). 



47 from the Lower, Middle, and Upper Llandovery. 

 8 from the Wenlock. 



28 from the Ludlow. 



It is also evident that in Scotland the largest number of species have been got from 

 the Llandeilo ; of these about — 



22 are common to the Llandeilo and the Caradoc. 

 7 pass from the latter formation into the Llandoveri/, 3 into the Wenlock, and 1 into 

 the Ludlow. 



Of the Caradoc species, II pass into the Llandovery (chiefly the Lower Llandovery), 

 17 from the Llandovery (chiefly the Upper Llandovery) into the Wenloch and Ludloiv. 



It is also evident even from these approximate and provisional estimates, that in 

 Scotland the large number of species are restricted to their formations. The Llandeilo 

 is extremely rich ; and, although only about a third of its species are found in the Caradoc 

 of Scotland, some more of them occur likewise in the Caradoc of England ; but the exact 

 line of separation between the Loiver Caradoc and Upper Llandeilo has still to be correctly 

 defined, as also the diff'erent horizons of the Llandeilo itself. Prof. Lapworth tells me that 

 the beds whicb contain the fossils of the Lower Girvan series, namely at Craighead, 

 Balcletchie, and Ardmillan Brae, are mapped in South Wales as Upper Llandeilo, in North 

 Wales as Bala, and in Shropshire as Caradoc ; and that there is much to be done before 

 we can sort out the different strata properly. The Upper Llandeilo and Lower Caradoc 



