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Clays, stretched away into Herefordshire. The rock under their feet was called 

 the Old Red Conglomerate, and they would see that it was made up of hard quartz 

 pebbles, and small grains of quartz, which might be compared to coarse sand. 

 They would observe that the pebbles and grains of quartz had been rounded, 

 which was evidence of their having been rolled about by the force of water. The 

 deposit was a sedimentary one, and represented the floor of an expanse of sea or large 

 inland lake. As to which of these two conditions existed at the time of the Old 

 Red Sandstone formation, there was a difiference of opinion. If they went into 

 Devonshire, they would find rocks of the same age which were undoubtedly of 

 marine origin ; this fact was proved by the corals and marine shells found as fos.sils 

 in the strata. On the other hand the fossils found in Devonian strata represented 

 by the Old Red Sandstone were mostly of a type which inhabit fresh water. The 

 Old Red Sandstone had sometimes been referred to as the "Age of Fishes," so 

 numerous were they in those days. They belonged to the Plaeoid and Ganoid 

 orders, and were distinguished, among other features, from the bone fishes of later 

 periods, by the skeleton being of a cartilaginous nature. At last the Old Red 

 Sandstone period came to an end, and was followed by the Carboniferous Epoch, 

 to which England owed so much as being the source of our coal supply. The 

 physical changes which took place could be well traced in the locality they were 

 about to visit. As they proceeded in the direction of Drybrook, they would find 

 that the Conglomerate, on which they were now standing, gradually changed ; 

 the quartz pebbles would become less numerous and be replaced by sandy beds, 

 with an extraordinary variety of colour. If they examined the mineral grains of 

 which those sandy beds were made up, they would detect them to be the remains 

 of broken up and decomposed granitic rocks, thus showing that the material had 

 been derived from the denudation of an ancient land surface of granitic rocks. 

 These interesting beds simply represented a transition period ; and soon vast 

 numbers of marine calcareous organisms were to appear, and by their death their 

 calcareous remains were to build up limestone rocks. If they, the Club, followed 

 the Sandy Beds in ascending order, they would find that they gradually passed into 

 Limestones and Shales. They had now arrived at the base of the Carboniferous 

 Period, at rocks known as the Lower Limestone Shales. To understand those 

 beds, and to realise what they taught, it was necessary to study them under the 

 microscope, which was only to be done by reducing portions to thin sections, so 

 that light could be transmitted through. He could not well bring a microscope, 

 but he had brought some photographs of the sections taken directly from the 

 microscope. One bed showed that it was made up of the remains of Encrinites, 

 or Stone Lilies as they were sometimes called ; another of the valves of Ostracoda, 

 an order of small Crustaceans ; in another Polyzoa, or Sea-mats, were numerous, 

 and the remains of shells. An examination of a number of these sections of the 

 beds showed that the Lower Limestone Shales represented a succession of sea 

 floors. The Organisms lived in the waters of that sea, and by their death the 

 Limestones were formed from the calcareous portion of their structure, which 

 accumulated at the bottom. The formation of the strata doubtless extended over 

 a long period of time, during which the physical conditions were varied, and thus 



