364 Prof. T. G. Bonney — Llgurian and Tuscan Serpentines. 



here I was not able to obtain any good specimens from rocks in situ. 

 The shore, however, especially about Pegli, is strewn with small 

 boulders and pebbles of dark green serpentine, which have probably 

 been brought from inland by the Varenna torrent. 



I observed two varieties : one a very dark green, nearly black, 

 rock, with numerous crystals of bronzite, very like the black 

 serpentine of Cadgwith ; the other rather harder and almost free from 

 included crystals. The latter did not seem likely to offer anything 

 of interest for the microscope, and I already possessed a slide cut 

 from a rock closely corresponding with the other ; so that, as these 

 specimens are not in situ, I have not investigated them microscopically ; 

 indeed, I feel justified, from their general identity in appearance 

 with the serpentines of Cadgwith * and Colmonell, 2 in claiming for 

 them a similar origin, without further examination. 



The railway from Genoa to Spezzia traverses a large mass of 

 serpentine, which forms the coast-line for several miles. It is first 

 seen at Framura, and extends as far as Bonasola, being much decom- 

 posed, and exhibiting in places a curious subspheroidal structure. In 

 colour it is sometimes a dull rusty red, sometimes greenish. Just 

 south of the latter place occurs a considerable mass of coarse gabbro, 

 composed evidently of " saussurite " and a greenish pyroxenic con- 

 stituent. Serpentine is exposed along the coast, and obviously extends 

 far inland up to Levanto and on to Monterosso. Just north of that 

 village it comes to an end ; and on emerging from a tunnel we find 

 at the station a dark coloured rock, which is now rather schistose 

 looking, and greatly crumpled and crushed, but appears to have 

 been originally a shale with irregular stony bands or concretions. 



After crossing this section in the train I returned to Levanto 

 (where I had observed quarries), in order to examine the serpentine 

 more closely. From this place the serpentine extends a considerable 

 distance inland. Just north of the village are numerous small pits, 

 and excellent specimens of the rock may be obtained. There are 

 two varieties : one, the commoner, a purplish or brownish black rock, 

 veined occasionally with dull green, and with crystalline folia of 

 glittering bronzite — very similar to the rock already described ; the 

 other, of a more granular texture and rougher fracture, also dis- 

 tinctly " tougher " under the hammer, rather greener in colour, with 

 a less metallic lustre on the included mineral. South of the village 

 is also serpentine. The first rock which is exposed on the shore is a 

 breccia (the fragments resembling the former of the above serpen- 

 tines and just beyond it is a great dyke (not less than seven yards 

 wide) of very coarse gabbro. The gabbro is rather decomposed and 

 consists of " saussurite " and diallage — the former decidedly pre- 

 dominating, and the crystals of the latter often 1 inch and sometimes 

 2 inches in diameter. Bej'ond this is more serpentine. 



Magnificent quarried blocks of beautiful brecciated serpentine 

 were lying near the railway awaiting shipment. On inquiry, I 

 found the quarries were some four or five miles distant among the 



1 Quart. Journ. Geol. Soc. vol. xxxiii. p. 890. 



2 Quart. Journ. Geol. Soc. vol. xxxiv. p. 770. 



