74 Notices of Memoirs — 



was wholly centrifugal in development, the first-formed tracheides 

 lying on the border of the pith, at the points marked by the carinal 

 canals. In Sphenophyllum, on the one hand, the whole of the primary 

 wood was centripetally developed, and there was no pith. In 

 Cheirostrobus the same holds good, except that an insignificant 

 portion of the primary wood may possibly have been added in 

 a centrifugal direction. In Lycopods there may or may not be 

 a pith, but the whole (Lycopodium, Psilotum, Zepidodendron) or the 

 greater part (Tmesipteris) of the primary wood is centripetal. 



The Calamite which forms the subject of the present communication 

 occurs in the well-known Burntisland beds of the Calciferous Sand- 

 stone Series, at the base of the Carboniferous formation. The 

 material is calcified, and the structure excellently preserved, though 

 the specimens so far discovered are small and fragmentary. Their 

 interest depends on the fact that each vascular bundle possesses 

 a distinct arc of centripetal wood on the side towards the pith. The 

 carinal canals are present, as in an ordinary Calamite, and contain, 

 as usual, the remains of the disorganized protoxylem. They do not, 

 however, as in other Equisetales, form the inner limit of the wood, 

 but xylem of a considerable thickness, and consisting of typical 

 tracheides, extends into the pith on the inner side of the canal, which 

 is thus completely enclosed by the wood. Hence, starting from the 

 spiral tracheides of the protoxylem, there was here a considerable 

 development of xylem in a centripetal as well as in a centrifugal 

 direction. That the organ was a stem, and not a root, is proved, 

 not only by the presence of the carinal canals, but by the occurrence 

 of nodes, at which the outgoing leaf-traces are clearly seen. 



This appears to be the first case of centripetal wood observed in 

 a Calamarian stem, and thus serves to furnish a new link between 

 the Palasozoic Equisetales and the Spenophyllales, and through them 

 with the Lycopods. 



The specimens have not as yet supplied any evidence as to the 

 superposition or alternation of the verticils, so we are not at pi*esent 

 in a position to determine the genus to which they belonged. Pro- 

 visionally, until further investigation has cleared up this question, 

 the new stem may bear the name of Calamites pettycurensis, from 

 the locality where it occurs. 



II. — The Scottish Okes of Copper in their Geological Eelations. 

 By J. G. GooDOHiLD, F.G.S.' 



THE ores of copper occurring in Scotland appear, so far as their 

 origin is concerned, to be referable to two primaiy categories. 

 The first of these includes those minerals whose origin is evidently 

 connected with the uprise of thermal waters ; and the second 

 includes those which are due almost entirely to deposition of 

 materials carried down in solution from some rocks at a higher 

 level to others below. The two methods of origin may be likened 

 to the ebb and the flow of the tides. 



^ Kead before the British Association, Section C (Geology), Glasgow, Sept., 1901. 



