The Quarterly journal of the Geological Society of London . Fig. 2.—Section of the installment nsed in surveying andlevelling the surfaces of septa and 30 PEOF. H. H. SWIXXEETOX AXD ME. A. E. TEUEMAX [vol. Ixxiii, The table was then rotated through a certain lumiber of degrees,and another diameter was brought into line Avith the direction oftravel. This process was re^^eated until readings had been takenalong a sutheient number of radial lines to allow of a contouredplan being made. Though this plan proved of great value, itcould not be ]-elied upon to record certain details, inasmuc
The Quarterly journal of the Geological Society of London . Fig. 2.—Section of the installment nsed in surveying andlevelling the surfaces of septa and 30 PEOF. H. H. SWIXXEETOX AXD ME. A. E. TEUEMAX [vol. Ixxiii, The table was then rotated through a certain lumiber of degrees,and another diameter was brought into line Avith the direction oftravel. This process was re^^eated until readings had been takenalong a sutheient number of radial lines to allow of a contouredplan being made. Though this plan proved of great value, itcould not be ]-elied upon to record certain details, inasmuch as anyportion of the septal svuface which tended to be an * under-cutcould not be registered by the vertically moving needle. In the preparation of a plan (figs. 11,11. & 17, pp. 44, 46, & 49)showing the precise position of successive surfaces produced b} filing,the following procedure was adopted. A portion of an adult whorl,containing at least one septum, was isolated, and the ends wereground flat and polished along a plane parallel to that of the specimen was then placed on the turn-table, with one of its endspressed against the po
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Keywords: ., bookcentury1800, bookdecade1840, booksubjectgeology, bookyear1845
