236 CARBONIFÈRE MARIN DE LA FRANCE CENTRALE. 



LOCALITES TOURNAISIENNES. 



HooK-PoiNT (Irlande). 



Il y a déjà plusieurs années que de Koninck a contribué à l'illustration du 

 célèbre gisement d'Hook-Point, au sud du comté de Wexford en Irlande, en 

 démontrant le synchronisme de sa faune avec celle de Tournai. Avant d'indi- 

 quer les espèces communes qu'il y a signalées, je reproduirai avec plaisir la 

 description de cette localité donnée par M. John Kelly et qui est peu connue en 

 France. 



« Hook Head or Hook-Point, in Wexford, is situated on the east side of 

 » Waterford Harbour, and the shore hère atîords a fine section of the lower 

 » part of the carboniferous rocks. First, red conglomérâtes and red sandstone, 

 » with some beds of yellow in ascending southwards, and a few beds of red 

 » or blue shale ; the upper part ail yellow or gray, and a little calcareous, and 

 » it is in thèse the fossils fîrst appears. Next cornes a séries of thin beds of 

 » limestone, and black shale alternating. The limestone rises in large flags, of 

 » which both sidcs are covered with a profusion and variety of fossils. The is 

 » on the townland of Portersgate. Over it lie yellow sandstone and calcareous 

 » gray sandstone, and this again is succeeded by thin beds and afterwards thick 

 » beds of limestone alternating with shale, for more than a mile along the 

 » shore, but nearly level. Next, towards Hook-Point, the wholc becomes limes- 

 » tone, with but a few and very thin beds of shale. In the whole Peninsula, the 

 » rock is so well exposed along the sca-shore that it is one of the flncst locali- 

 » lies in Ireland for fossils. Very fine spécimens of crinoïd hcads hâve been 

 » found near the Point. They are usually got in the thin beds of shale which 

 » separate the limestone beds, where the action of the waves carries away the 

 » soft matter of the shale and leaves them standing in relief on the surface of 

 » the bed of limestone. In consideringthem, on the spot, the idea is suggested 

 » that they grew on the surface of a bed of limestone in the sca — as seaweed 

 » now does — that a flood came over the place, charged with sand and mud, 

 » and killed the animais, which, therefore, lay dead, and ware buried in the 

 » muddy deposit left by the waters, which is usually from thrce to six inches 

 » thick between the beds of limestone. The heads and stems, for some feet in 

 » length, are got togethcr, lying in thèse thin shale beds, and in some cases 

 » hâve ail their fine markings bcautifully shown '''. » 



(1) John Kelly Esq. On Iccalities of fossils of the carboniferous limestone of Ireland. Journ. of the 

 Geol. Soc. of Dublin. 14 mars 1855, p. 43. 



