256 SCIENCE PROGRESS. 



Calamitean stems so far discovered in this country, belong- 

 to the Arthropitoid type, in which the structure of the wood 

 is less complex. 



A passage from the autobiographical notes already 

 mentioned refers to this time, and gives an interesting idea 

 of the spirit in which the work was undertaken : — 



" I then formed a resolution which has been of the 

 greatest service to me. Remembering how I had been 

 misled in my early researches amongst the Foraminifera, by 

 the authority of Ehrenberg, I determined not to look up the 

 writings of any other observers until I had studied every 

 specimen in my cabinets, and arrived at my own conclusions 

 as to what they taught. Having thus formed my own in- 

 dependent judgment, I then turned to the works of other 

 observers in the same fields to learn in detail what their 

 views were." 



To this resolution not only the great merits, but also 

 some of the defects of Williamson's work may be traced. 

 All his writings bear the stamp of absolute originality, and 

 are free from the wearisome load of literary recapitulation by 

 which so many modern scientific treatises are burdened. On 

 the other hand, no one man's work can form a sufficient basis 

 for valid generalisation, and in some cases Williamson 

 would doubtless have arrived sooner at true conclusions if 

 he had allowed himself to be a little more influenced bv the 

 researches of others. 



But no investigator, however independent his spirit, 

 could succeed in making his mind an absolute tabula rasa 

 to start with, and so we naturally find some traces of the 

 influence of the great Brongniart in Williamson's earlier 

 papers. In the memoir of 1869 (p. 173) he says: "The 

 Calamites seem to me to constitute a well-defined link con- 

 necting the Exogens with the Acrogens ". Brongniart, as 

 is well known, had in his earlier works united all the 

 Calamites in one group, but had afterwards separated those 

 with exogenous (or, as we should now call it, secondary )growth 

 under the name of Calamodendron, reserving- the genus 

 Calamites for forms supposed to be destitute of secondary 

 tissues. The former he regarded as " Gymnospermous 



