The Kelhead Fossils. 207 



of Kelhead Quarry during his stay in Annan. A representative 

 group was sent here to form the nucleus of a local collection, but 

 the specimens of greater rarity were forwarded to the British 

 Museum, and retained there on account of their great value. 



It is now universally admitted that every succes.sive deposit 

 of sediment is characterised hy a higher type of animal or vege- 

 table life than that which is found in the older or underlying 

 strata. This progression or evolution of life is in some cases so 

 pronounced that one continuous deposit of sediment may be 

 readily divided into various groups or zones. Each zone is 

 named after the fossils peculiar to itself, and occupies a definite 

 position or vertical range in the ascending series of deposits. 



Fixing the zones b}- means of their fossils enables us not only 

 to ascribe them to definite ages, but also to co-relate rock 

 exposures with their equivalents, even when geographically 

 remote. • 



Unfortunately, V' e Carboniferous rocks of Scotland have not 

 yet been shown to possess this zonal succes.sion in the same degree 

 as the Silurian and Jurassic formations do. For several years 

 geologists have been endea\ouring to co-relate the various Car- 

 boniferous basins in Scotland with each other and with their 

 equivalents in England. 



The great difference between the alternating bands of sand- 

 stones and shales in Scotland, on the one hand, and the massive 

 beds of limestone in England, on the other, is very pronounced. 

 Therefore, from its peculiar geographical position between the 

 Northern and Southern types, the Annandale strata represents 

 the actual scene of the transition. 



A careful study of the fossil list will show a complete agree- 

 ment with other collections from the Lower Limestones of Scot- 

 land — particularly with the band known as the Main or Hurlet 

 Limestone. The great abundance of Product us giganteus and 

 the presence of Corals (Lithostrotions) co-relate the Kelhead 

 Limestones with the Five. Yard Limestone of East Westmore- 

 land and the Eelwell Limestone of Northumberland. In the 

 Clyde area this horizon (the Main Limestone) is underlain by 

 a great mass of volcanic la\'a several thousand feet thick ; in 

 Cumberland there is no trace of any such outburst, but in the 

 Kelhead section the White band gives clear indication of the 

 proximity of volcanic activity. The purit}- of the Limestone 



