C. H. White — Autophytography. 



235 



differs from the last only in having a darker iron-pigment in 

 the rock, and in the form of the root reproduced, but in neither 

 case is the portion of the plant reproduced sufficiently charac- 

 teristic to identify the species. 



These antophytographs belong in no sense to a past geolog- 

 ical age. They were formed on or near the present land sur- 

 face and show little evidence of having suffered disintegration 

 and erosion. Granting that in transportation and deposition 

 the probabilities are decidedly in favor of the destruction of 

 these plant records, yet there are conditions of deposition and 



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burial, not at all rare in nature, that would very effectively 

 preserve such records to future geological time. "While the 

 specimens so far considered belong to the present and have no 

 value as records for the historical geologist or palaeontologist, 

 they well illustrate the process of autophytography and, as just 

 pointed out, lead us to expect fossils of this character in the 

 plant-bearing horizons of past geological time. 



At the suggestion of Professor R. T. Jackson, the collection 

 of fossil plants in the Harvard Botanical Museum was inspected, 

 and it was found that fossil plants from many horizons partake 

 of the quality of the autophytograph of both the positive and 

 the negative type. Plant impressions in the slates at Solen- 

 hofen, Bavaria, marked out by oxide of iron have been observed 



