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GEOLOGICAL COLLECTIONS. 



Instructions for the Collection of Geological Specimens ; {issued by the Geolo- 

 gical Society.) 



1. The Geological Society begs to impress upon the minds of all collectors, 

 that the chief objects of their research should be specimens of all those rocks, 

 marls, or clays, which contain shells, plants, or any sort of petrifaction. 



2. The petrifactions should, if possible, be kept united with portions of the 

 rock, sand, or clay, in which they are found ; it being more desirable that the 

 mass should be examined carefully when brought to England, than that any 

 separation of the shells should be attempted at the time of their collection. This 

 injunction, however, does not apply to those cases in which the shells fall readily 

 from their surrounding matrix ; but, in this event, great care must be taken of 

 the petrifactions, by rolling them in paper, or some soft material. 



3. If several varieties of stone are seen in the same cliff or quarry, and parti- 

 cularly if they contain any petrifactions, specimens of each should be taken, and 

 numbered according to their order of succession ; marking the uppermost No. 1., 

 and thence descending with Nos. 2, 3, &c., making as correct an estimate as 

 time will permit, of the thickness of the beds. None of these specimens need be 

 more than 3 in. square, and one and a half or two thick. 



4. If the rocks are stratified, that is, divided into beds, state whether they are 

 horizontal, inclined, or twisted. If inclined, observe pretty nearly at what angle, 

 and to what point of the compass they dip ; if twisted, a sketch, however slight, 

 is desirable — N.B. The true dip can seldom be ascertained without examining 

 the beds on more sides than one. 



5. One kind of rock is occasionally seen to cross and cut through the beds of 

 another. In such a case, observe whether the beds are in the same plane on each 

 side of the intruding rock ; if not, mark the extent of the disturbance, and also, 

 if there be any difference in the nature of the stone of which the beds are com- 

 posed, at those points where they touch the intruding rock. Take specimens 

 from the junction, and make a sketch of it. 



6. Where there are wells, get a list of the beds sunk through in digging them ; 

 specifying the thickness of each stratum in its order, from the surface downwards. 



7. In volcanic districts, procure a list of the volcanoes now or recently in ac- 

 tion, and of those which are extinct ; stating their position, their distance from 

 the sea or any great lake ; the extent, nature, and, if possible, the age, of parti- 

 cular streams of lava, or the relative age of different streams : also, whether the 

 lava currents conform to the valleys, for are seen at different heights above the 

 present rivers : and also if any gravel beds be discoverable beneath the streams 

 of lava. 



8. Note the names of all places known to contain coal, bitumen, salt, alabas- 

 ter, metallic ores, or any valuable minerals, specifying their extent, and the na- 

 ture of the rocks in which they occur ; but do not bring away large quantities of 

 iron ore, spar, salt, &c. 



9. In cases of coal-pits, specimens of the coal itself and of the beds passed 

 through to obtain it, (especially when plants have been found,) will be valuable. 

 State whether limestone, iron ore, or springs of bitumen, are found near the coal ; 

 and if the limestone contains shells, collect abundance of them. 



10. Make particular inquiries whether, in digging gravel-pits, or beds of sur- 

 face clay, mud, and sand, the workmen are in the habit of finding any bones of 

 quadrupeds ; and obtain as many of them as possible, selecting particularly teeth 

 and vertebrae. 



11. Search also for bones in cracks of rocks, and in caverns. In the latter, 

 the lowest pits or hollows are most likely to contain bones ; and if the solid rock 



