26 Armitagb, Plant Remains in Olivine-BasalL {^^'^^iunt^^' 



Mr. Harker regards this agglomerate as having consolidated 

 from material ejected from a Tertiary volcano, and containing in 

 it, among other material, derivative fossil wood brought up by 

 volcanic action from Oolitic strata beneath the basalts. Across 

 these basalts and agglomerate has subsequently been intruded a 

 hypabyssal pitchstone complex, which, as it passed the ag- 

 glomerate band containing the fossil wood, had taken up a log 

 and smaller pieces and included them in itself. He further 

 states : — " In the lower part of the pale decomposed pitchstone, 

 but distinctly enclosed in it, occurs the main mass of the wood 

 which has furnished the specimens of Pinites eigyensis. There 

 can be no doubt that this (as well as the Torridonian fragments) 

 has been taken up from the underlying breccia. Most of the 

 wood both in the main mass and in the scattered pieces is com- 

 pletely silicified, of a lustrous black, and often shot through with 

 slender threads of white calcite ; but there is some which is not 

 silicified, being more or less carbonized, with a similar black, 

 lustrous aspect." 



About eight feet of this wood was exposed as a log with a 

 flattened oval outline in transverse section about eight inches in 

 vertical height. Smaller pieces were found near this log. As 

 well as these pieces in the pitchstone, those in the agglomerate 

 beneath are described. 



Dr. Solorzano and Mr. Hobson (15) recently described a 

 specimen which is to be seen in the museum of the College of 

 St. Nicholas (founded in 1540), in the city of Morelia, Mexico. 



Dr. Solorzano writes (trans.): — "I will mention another 

 volcanic product wliich .... is exceedingly interesting, 

 since it proves not only the small conductivity of lavas in spite of 

 their very high temperature, but also indicates, to a certain 

 extent, the epoch in which volcanic phenomena were in full 

 activity in the region where the rock I refer to was collected. 

 It is a basaltic scoria which shows numerous and 

 very distinct external impressions of female ears of maize and 

 also entire grains and carbonized remains of the axis of the 

 ear. This seems to show that the inhabitants of the locality in 

 question cultivated the plant just mentioned when a volcano (one 

 of the extinct ones which exist between Quiroga and Patzcuara) 

 made the eruption which ejected the rock above described." 



Summing up the above references, we find records as follows : — 



{a) Fouque, Guillemard, Dana, Diller, and Solorzano and 

 Hobson — Plant remains preserved during historical times in 

 lavas of various kinds. 



(6) Macculloch — Carbonized wood in Tertiary trap conglomerate. 



(c) Cadell, and Walcott — Pseudomorphous replacements of plant 



remains in Tertiary basalt. 



(d) Harker — Derivative Oolitic fossil silicified wood in Tertiary 



hypabyssal pitchstone. 



