52 Transactions. 



three feet square, sloping oli" east and west from a central ridge, 

 saddle-like, is covered as closely and intricately as possible with 

 designs of a similar type to those shown on PI. III., of which) 

 indeed, it forms a portion. Several square feet to the east of 

 this sculptured " saddle " are also very elaborately carved with 

 what seem, at first glance, to be fresh designs, in which grooves 

 straight and partly angular are more conspicuous than rings. 

 There are also many small groupings of cups in threes and fives, 

 some with grooves, others simple. The chief peculiarity in the 

 portion shown in my diagram (Fig. 3, PI. VII.) lies in the whole 

 inner surface of the ring marked A being hollowed out to a level 

 below the actual level of the surrounding rock. This ring is ten 

 inches wide, and the adjoining circle eleven inches. 



III. Tlie Grajytolites of the Moffat District. 

 By Mr James Dairon, F.G.S. 



It may be remembered that the specimens which I exhibited 

 before this Society on the last occasion were, with feAv exceptions^ 

 principally the simpler forms belonging to the genera Monograptus 

 and Diplograptus. To-night, I shall bring forward a few of the 

 more complex kinds, also found in the lower Silurian or upper 

 Llandeilo rocks of the south of Scotland from the localitj* of 

 Moflat. Although these ancient Zoophytes have not a wide 

 range in the earth's crust, being exclusively confined to the 

 Silurian system, yet, geographically speaking, they are found in 

 various countries of the globe, indeed wherever these rocks exist. 

 I shall again briefly describe their structure, and with the assist- 

 ance of this model, the accompanying drawings, and specimens 

 which are on the table, those of you who are unfamiliar with the 

 subject will, I trust, be able to follow me as I proceed in the 

 enumeration of the difierent species. 



We shall now notice Monograptus Sedgwickii. — There is no 

 Graptolite, it may be stated, that assumes so many different forms 

 and variations of form as this species. Many of these diff"erences, 

 I have no doubt, may arise from their state of preservation, their 

 age, or their sex. There are two or three varieties, which appear 

 to be distinct enough to be entitled to distinct names. The 

 general form of M. Sedgwickii, as described by Portlock and 

 figured by M'Ooy, consists of a simple Monoprionidian stipe of 



