The Geoloyy of Coiinaldai 181 



Permo-Carbonijerous Ghuial Beds. Umler tliis nauie we h;ive 

 grouped a series of beds occurring in the district which are either 

 of undoubted glacial origin or bear evidence tliat during their 

 formation glacial conditions supervened. They are mainly devel- 

 oped in the western part of the district between the Goodman's 

 Creek and Lerderderg River, many excellent sections being 

 exposed in these streams ; along the Pyrete and Back Creeks, 

 and in the area north of Coimaidai drained by Basin Creek. In 

 the absence of outcrops the nature of the sulijacent glacial beds 

 may be in many places plainlj' inferred from the profusion of 

 .striated boulders scattered over the surface of the ground. 



In our division and nomenclature of the glacial beds we adhere 

 to the plan adopted in our Brisbane paper, and classify them as 

 follows : — 



(1) Strati tied mudstones. 



(2) Glacial conglomerates. 



(3) Stratified sandstones and freestones. 



This ternnnology does not agree with that adopted by Professor 

 David in his paper read before the Geological Society of London 

 in February, 1896.^ The beds which we call glacial conglom- 

 erates are apparently the same as his hard glacial mudstones ; 

 the beds he describes as conglomerates are so sparingly developed 

 in the Coimaidai district as not to warrant a special division of 

 the beds to include them. The beds which he calls clay-slates 

 apparently correspond to our well stratitied mudstones ; we have 

 observed no bed in our district to which the term slate can be 

 properly applied. 



Stratified //ludstones. Tiie beds are tirst described, as they 

 form the lowest of the glacial series visible in our district. They 

 ■consist of regularly stratitied deposits of a more oi- le.ss hai'd 

 tenacious elay ; they are occasionally tinely laminated ; they vary 

 somewhat in colour, blue and yellow being the prevailing tints. 

 Their glacial character is at once attested by the number of 

 scored and scratched stones and l)Oulders, varying from mere 

 pebbks to huge rock-masses weighing tons, contained in them. 

 The included stones and boulders are for the most part scattered 

 iiTegularly through the matrix, but occasionally bands of these 



1 See Q..J.G.S., vol. lii., i-t. ii., No. "206. 



