166 DR. THOMAS STERRY HUNT ON THE 
$ 2. We find at the beginning of our century, that the most competent observers were 
agreed in regarding serpentines as stratified contemporaneous deposits in the so-called 
primary rocks. Patrin described those of Mont Rose and of the Rothhorn as inter- 
stratified with calcareous and micaceous schists, while Saussure found those of Mont Cer- 
vin to present similar conditions, and described certain serpentines, found near Genoa, as 
alternating with bands of calcareous, quartzose, and micaceous schists or argillites. 
Humboldt, in like manner, noticed the stratified character of the serpentines near Beyruth, 
and Jameson found those of Rothsay, in Scotland, to be interstratified with micaceous and 
talcose schists, and with crystalline limestone, in repeated alternations, of which he gives a 
diagram, mentioning, however, as an opinion held by some, that the masses both of ser- 
pentine and of limestone “form great veins rather than vertical sheets.” He elsewhere 
describes serpentine as a primitive stratified rock, contemporaneous, and alternating with 
crystalline schists.* 
§ 3. A little later we find, in 1826, Maculloch, in his Geological Classification of Rocks, 
separating the primitive rocks into two groups, stratified and unstratified, the latter con- 
sisting of granite and serpentine, He assigned as a reason for placing serpentine in the 
latter class that it does not appear to be decidedly stratified, but, at the same time, remarks 
that, unlike other unstratified rocks, as granite or trap, he had not found serpentines to 
present ramifying veins. Subsequent studies in the Shetland Isles led him to make what 
he calls “an important correction” in its history, in the Appendix to the volume just 
named, where he announces his conclusion that the serpentines are stratified rocks, like 
eneiss or mica-schists, adding a revised tabular view, in which they are included with 
these in the stratified division of the primitive rocks, granite alone being retained in the 
unstratified division. 
§ 4. Boase, in his Primary Geology, in 1834, describes the serpentines of Cornwall as 
associated with talcose and chloritic and actinolite-schists, and what had been “ called 
hornblende-slate,” to which the serpentine seemed in some instances subordinated. He 
further compares these associations and modes of occurrences with those described by 
Maceulloch.t De la Beche, in like manner, in his Geology of Cornwall and Devon, notes the 
seeming passage of the serpentine into the hornblende-slate in many places, but also its 
apparent “intrusion amid the latter with force ;” a seeming contradiction which he recog- 
nizes, but endeavors to explain.§ 
§ 5. Unlike Macculloch and Boase, De la Beche regarded serpentine as an eruptive rock 
of posterior origin to the associated schists, agreeing in this with Brongniart, who had 
placed serpentine among plutonic rocks. A similar view was held by Elie de Beaumont || 
and by Savi, and, without entering into further details, we may notice that they have been 
_ followed by Sismondi, Lory, and others, who maintain the plutonic origin of the Alpine 
serpentines, while, on the other hand, Scipion Gras, Gastaldi, Favre and Stapff regard them 

* See for the text of the above references the quotations in Pinkerton’s Petralogy, 1821, I. 334-343 ; II. 608:612, 
+ Maculloch, loc. cit., pp. 78, 243, 652-655. 
t Boase, loc. cit., p. 46. 
2 De la Beche, loc. cit., pp. 35, 99. 
|| After discussing the question with Elie de Beaumont in 1855, I asked his eminent colleague de Senarmont 
as to the eruptive origin of serpentines. He replied that his own extended studies of the serpentines of Europe 
had led him to reject, as wholly untenable, the theory of their plutonic origin. 
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