24 THE VOYAGE OF H.M.S. CHALLENGER. 



resume" of the results arrived at by the observers who have described the peridotites found 

 as regular intercalations in various formations. 



The first peridotic rock ever noticed was discovered by Lelievre in 1787; it was 

 named Iherzolite by De la Me'therie, 1 who mistook it for an essentially pyroxenic rock. 

 Damour 2 showed in 1862 that it consisted of two-thirds of olivine. According to the 

 researches of Charpentier 3 and Marrot, 4 that rock occurs in a Lias limestone, which in 

 contact with granite becomes transformed into granular limestone. Other communica- 

 tions on the Iherzolite published by Zirkel 5 leave some doubt on the question of origin. 

 Sandberger, on the other hand, does not consider the rock to be eruptive. 6 Des 

 Cloizeaux 7 has noticed some Iherzolites intercalated in the Silurian limestone of Eaux- 

 Bonnes (Basses Pyre'ne'es), and at Beyssac (Haute Loire), where they are found in a 

 granitic region. The olivine rock of Seefeld Alp, in Ultenthal, 8 to the south-east of 

 Meran in Tyrol, is intercalated in the crystalline schists. The peridotites discovered by 

 Sandberger 9 at Conradsreuth, near Hof, are, like the rock of Ultenthal, encased in 

 crystalline schists. Tschermak 10 showed afterwards that the peridotites in the region 

 of Karlstatten, Aggsbacch, and in the granulitic district of Lower Austria, are also inter- 

 bedded in crystalline schists. In Norway peridotites have been recognised by Kjerulf, 

 and Pettersen 11 has shown that peridotic rocks are intercalated in strata belonging to 

 the group of the mica schists of Tromso. Becke 12 in his recent work on the peridotites 

 of Greece does not consider them as eruptive. Giimbel in his geognostic description 

 of the Fichtelgebirge 13 admits that the serpentine rocks imbedded in the gneiss of the 

 Fichtelgebirge are altered peridotites. According to Axel Erdmann " the eulysites, so 

 similar to peridotic gneiss, are found in Sweden intercalated in gneiss in the neighbour- 

 hood of Tunaberg. 15 



1 De la Me'therie, The'orie de la Terre, vol. ii. p. 281. 



2 Bull, de la Soc. G6ol. de France, 2*>e Se"rie, vol. xix., 1862, et Neues Jahr. f. Min., 1863, p. 95. 



3 Charpentier, Essai sur la Constitution gdognostique des Pyre'ne'es, 1823, p. 245. 

 * Ann. des min., 2^e Serie, voL iv., 1828, p. 207. 



6 Zirkel, Zeitschrift d. d. geol. Ges., 1867, p. 136. 



6 Bonney's Memoir already quoted tends, on the contrary, to prove the eruptivity of the Iherzolite. 



7 Des Cloizeaux, Bull, de la Soc. Geol. de France, vol. xix. p. 48. 



8 The specimens of the Ultenthal rock I have seen in the collections show great analogies to the rock of St. 

 Paul, the only difference they offer in aspect consisting in the larger size of the grains. 



9 Sandberger, Neues Jahr. f. Min., 1866, p. 391. 



10 Tschermak, Sitzungsb. der. K. K. Akademie der Wien. Wiss., vol. Ivi., 1867. 



11 Pettersen, Neues Jahr. f. Min., 1876, p. 613. 



12 Becke, Tschermak, Mineralogische Mittheilungen, loc. dt. 



13 Giimbel, Geognostische Beschreibung des Fichtelgebirges, Gotha, 1879, p. 148. 



14 Neues Jahr. f. Min., 1849, p. 837, and Zirkel, Lehrbuch der Petrographie, voL ii. p. 335. 



15 It is important also to notice a communication in which Brb'gger (Neues Jahr. fur Miner, 1880, pp. 187-192) 

 clearly demonstrates the existence of schistoidal peridotic rocks in the Sondmore region. (See also H. H. Reusch, Das 

 Grundgebirge im Siidlichen Sondmore und in einem Theile von Wordfiord, Kristiania, 1877.) In the same number of 

 the Neues Jahr. fur Min., E. Cohen gives an account of a paper by Tornebohn (Mikroskopiska bergartes studies, 

 Geol. Fb'ren, i. Stockholm, Fb'rhandl., 1877, Bd. iii. No. 9), in which the latter describes the peridotite of KetillsfjalL 

 According to his description it must be very similar to the peridotite of St. Paul ; it is regularly intercalated in the 



