Page:A Treatise on Geology, volume 2.djvu/307

 CHAP. X. of Jura limestone there, range in a line N.E. and S.W. parallel to the summit ridge of the Côte d'Or. The line of these granite points being considered part of a geodesical circle, and prolonged in each direction, is found to coincide with several remarkable geological accidents or disturbances. In the N. E., for instance, it coincides with dolomitic oolite and steep dips at Sury, between Langres and Dijon; with the hot springs and magnesian muschelkalk of Bourbonne les Bains; with the basaltic eminence of Essey, of Luneville, and with the granitic protuberance of Albersweiler, between Annweiler and Landau.

Another line of disturbance, parallel to the preceding, is indicated; and it is observed that from Paray (Saone et Loire) to Plombières (Vosges), the great line of valley watered by the Bourbonne and Saone is perfectly parallel. This line, prolonged into Germany, passes along the valleys of the Mayn and the Saal, through Mittenberg to Leipzig, and is parallel to the Erzegebirge and Mittelgebirge.

Now all these dislocations were probably produced at the same geological epoch; which, though inferred from the general phenomena along the line, is determined more exactly in consequence of an extension of this system of faults by a series of parallels retiring to the S. E., till we arrive in the department of the Rhone, where the chalk and Jura limestones are found together—the latter dislocated, the former undisturbed. The direction of this line of disruption is N. E. and S. W. at Dijon.

In the Jura, a great number of undulations in the strata range parallel to a line N. 40° E., or N. 45° E.; and, being sometimes filled with green sand deposits, are clearly of the same date as the above disruptions.

In abstracting the proofs of the other grand systems of elevations, we shall attend less to the minute than to the general analogies. The insulated chain of the Pyrenees, one of the most remarkable in Europe, forms the base of the system. Many observations prove that the chalk