Lapworth & Wilson — Silurian Rocks of Roxburgh & SelkirJc. 463 



membered that the officers of the Geological Survey, with all their 

 experience, mapped the whole of Haddington and the North of 

 Berwickshire without detecting more than two Graptolites in the 

 whole of the Gala beds of that district, and added but a single 

 species in Peeblesshire to our Grieston Fauna — when it is known 

 that the most careful examination of the large tracts is often entirely 

 fruitless, and that the majority of the fossil beds only yielded up 

 their remains after having been examined without result again and 

 again — the interest and value of the fossils yet obtained is seen to be 

 very great. 



We have made out about forty species from the Moffat series, a 

 little less from the Gala group, and only about a dozen as yet from 

 the Riccarton beds. 



An examination of these fossils shows us the enormous predomi- 

 nance of the Graptolites. These peculiar creatures have never yet 

 received the attention they deserve, and those of Britain have been 

 treated so carelessly that the real horizon of some of the species 

 cannot be even guessed at. 



Enough, however, is known of their localities in the North of 

 England, in Bohemia, and in North America, to enable us to speak 

 pretty confidently as to the range of many of the forms in the 

 Silurian system, and to fix approximately at least the age of the 

 Gala and Moffat formations. 



It would greatly lengthen this paper were we to lay all the 

 evidence before you in order, but it is sufficient for our present 

 purpose merely to state the conclusions at which we have arrived. 



A careful comparison of the Moffat Graptolites with those of other 

 countries has convinced us that these beds should be classed with 

 the Utica Slate and Hudson Eiver Group of North America and the 

 Graptolite-bearing schist of Wexford and Waterford ; in other words, 

 that they are of Bala age, or bridge over the gap between the Bala 

 and Llandeilo. 



The fossils of the Gala Group lead us to place it high in the 

 Lower Silurian, and to believe that it is very probable that some of 

 the higher beds are of Upper Silurian age. Its fauna approximates 

 most closely to that of the Coniston mud-stones of Cumberland and 

 Westmoreland, and which are placed by the Geological Survey of 

 England at the base of the Upper Silurian ; it has also a very close 

 relationship to that of Barrande's Colonies and the band E. e. 1, the 

 last of which is also classed with the Upper Division. 



Such, then, is a summai'y, as short as we can make it, of the work 

 already done by us in these old sedimentary deposits ; very little, it 

 is true, in comparison with what yet remains to be done in the future, 

 but enough to encourage us to persevere. 



We have purposely abstained from comparing the structure of this 

 district with that further to the west, leaving the task to those who 

 are more familiar with that country. We believe that our sub- 

 divisions (which are those into which our strata naturally fall), for 

 this district at least, will, in effect, ultimately be adopted. We hold 

 that our Upper Groups can be separated from each other, even 



