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LocalitiesOld Saybrook, Middlesex County, Connecticut, USA

24th Jan 2012 23:19 UTCHarold Moritz 🌟 Expert

I see that several minerals have been attributed to this town using Robinson's 1825 Catalog of American Minerals as a reference. This is incorrect as Robinson was actually referring to "Saybrook" which is not equivalent to the modern town of Old Saybrook. Saybrook colony was established in 1635 and merged with the Connecticut colony in 1644. Various portions split off and became incorporated over time as the towns of Lyme (1665), Old Lyme (from Lyme) (1855), East Lyme (from Lyme) (1839), Chester (1836), Westbrook (1840), Essex (1852, known as Pettipaug, Pettypaug, or Potopaug until 1854), and Old Saybrook (1854). The remainder, surrounding the original core town of Saybrook, changed its name to Deep River in 1947. Thus minerals attributed to "Saybrook" in Robinson (1825) could include mineral localities now in any or all of these towns other than the Lymes. The reference includes entries for "Chester Parish. See Saybrook"and "Pettypaug. See Saybrook" and "Saybrook" (but no entry for Lyme). In general, using Robinson 1825 as a reference requires checking the many changes in Conn. geography since 1825 to properly attribute mineral localities.

Here is the text from Robinson regarding minerals from Saybrook:

Epidote, crystallized.
Apophyllite; near.
Actynolite.
Anthophyllite. This rare mineral is said to have been found near this town.
Chlorite, in small crystals.

Sillimanite. This mineral, previously called anthophylite, is of a dark grey color, passing into clove brown. It occurs in rhomboidal prisms. It has but one cleavage, which is parallel to the longer diagonal of the prism. The sides and angles of the crystals are frequently rounded. It is harder than quartz,—found in a vein of quartz penetrating gneiss. (Sil. 8.113.) This locality is on the turnpike leading from Saybrook to Middletown, not far from 2 1/2 m. beyond the locality of molybdena, in the parish of Chester, on the left hand of the path, in a flat rock which is chiefly mica slate, a few rods S. of the Post Office, which is kept in a room of Denison's tavern, near a small stream running into the Connecticut—crystallized in veins of quartz. (Sil. 8.195.) The writer is informed that the above mineral was previously named in Europe, and has been since known there by the name of Mc Clellanite.

Sulphuret of Molybdena, a small distance northerly from Pettypaug m. h. in a vein of quartz traversing gneiss, (C.) ½ a m E. of the Middletown turnpike, near the house of the Widow Pratt, on the first road on the right hand, above the turnpike gate. (Sil. 1.242.)

The epidote and chlorite localities are uncertain, as is the actinolite, though they are plausible given the metamorphic terrane here. At best these should be attributed to Middlesex County as they could be from a number of towns. Anthophyllite is erroneous (as reported by Bowen in his 1824 type description, this is what the sillimanite crystals were thought to be previously) and apophyllite is very likely a confusion with anthophyllite as the right rocks for apophyllite do not occur here and it has never been found in the area since.

What is certain is that the sillimanite locality description is the type locality, now in Chester, and the molybdenite locality is now in Essex. Mindat pages for these will be created. I visited the sillimanite type locality today and it is in the very center of town and now completely developed, no outcrops are evident. Even in 1817 when it was found the area would have been developed). However, the person who provided Bowen with the locality information said it was "in a flat rock" that is "mica slate" (schistose gneiss) and there are still abundant loose slabs of gray gneiss of the Tatnic Hill Formation along Pattaconk Brook and in stone walls in the immediate area. I believe the crystals were in a loose slab and not in an outcrop.

25th Jan 2012 00:59 UTCPeter Cristofono

Hi Fritz,

Thanks for doing all of this research and for your field report on the sillimanite type locality!

Best,

Peter

25th Jan 2012 02:29 UTCHarold Moritz 🌟 Expert

One revision, anthophyllite is mapped in the Middletown formation within parts of the former Saybrook area according to, for example, Lundgren (1963) Bedrock Geology of the Deep River Quad. It explains its confusion with the brown-gray sillimanite from the type locality. Peter, do you know where the Harvard specimen came from?

25th Jan 2012 02:39 UTCPeter Cristofono

I assume you mean this photo: sillimanite

I'll make an inquiry for you.

25th Jan 2012 19:36 UTCHarold Moritz 🌟 Expert

Yes, it looks very much like type material, which besides being in a quartz vein cross-cutting gneiss, is described by Bowen (1823 & 1824) as "dark gray, passing into clove brown. It occurs crystallized in rhomboidal prisms, whose angles are about 106° 30' and 73° 70'; the inclination of the base to the axis of the prism being 113°. It has but one cleavage which is parallel to the longer diagonal of the prism. The sides and angles of the crystals are frequently rounded." Thomson (1845) describes them as "several inches long". These characteristics seem to match the photo of the Harvard specimen. Would love to examine it to see if the matrix around the quartz (if any) matches the Tatnic Hill Formation. What is that red stuff on it, looks like wax or something?

27th Jan 2012 14:58 UTCPeter Cristofono

Hi Fritz,

The Harvard Museum database for this specimen only indicates that it is sillimanite from Chester. Unfortunately, there is no other information. Not sure what the red stuff, is - looks to me like iron oxide. I'd have to take a look again at the specimen (it's down in the basement storage area) to tell you more. Next time I'm there, I'll check it out.

Peter

27th Jan 2012 17:41 UTCHarold Moritz 🌟 Expert

Hi Peter:

I have never seen any other reference to any other mineral locality in Chester. As the specimen is only labeled "Chester" it must be type material, sure looks like it. Date of acquisition and from whom would help.

Thanks

Fritz

28th Jan 2012 01:35 UTCPeter Cristofono

Fritz,

The 85xxxx specimen number means that it must have been acquired by Harvard in the early 1920s. For example, #86694 (ruby) was acquired in 1925; and #89815 - rhodonite - was field collected in 1927.

Compare this Harvard specimen of "Chlorophyllite" from its type locality, # 85305. It was in the collection of JD Whitney (1819-1896) so it was a nineteenth century specimen, but the 85xxxx indicates that it was acquired around the time of the sillimanite specimen.

Peter

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