Lee B. Hotchkiss and Beverly Stern
Mr. Jefferson’s Embargo of 1808 and “Mr. Madison’s War” a few years later not only crippled New England shipping enterprises; they also changed the emphasis of the economy from agriculture to industry. Banks replaced merchants, and capital moved into a new ventures, notably manufactories. Connecticut was in the van of this development because of its cheap water power and its easy access to markets. Factories appeared in great numbers along rivers and streams. The Mill River is a foremost illustration of this new and growing economy.
Some of the nineteenth-century industries on the Mill River follow. They are listed to show diversity and are not listed chronologically.
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NOTE: Above information on Mill River industries is extracted from Rachel M. Hartley,
The History of Hamden
,
Connecticut
, 1786-1936. Hamden: 1943 and Rollin G. Osterweis,
Three Centuries of New Haven
,
1638-1938
. New Haven: Yale University Press, 1953.
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Geology and Nature Field Trip of the Mill River and the East Rock Area
Area
A walk along the Mill River from Orange Street Bridge to Lake Whitney
Materials
Map of the area (Adapted from City of New Haven Engineer’s Map by Philip M. Orville); pencil, pad, protractor, hand lens, collecting bottles and a plastic bag for specimens.
Background Information
Looking up at East Rock you see the main mass is a sill (an igneous rock that has intruded between layers of sedimentary rock). This intrusive, igneous, lava rock is composed of black to dark green minerals and called dolerite, basalt or traprock (referring to the columns that resemble steps) and is very resistant to erosion. It is interesting to look at freshly broken fragments of basalt that are blackish whereas the weathered surface of the freshly broken talus fragments have a rusty orange color due to iron in its composition. Notice the large columns of dolerite that were formed when the lava contracted. Millions of years of weathering wore down these uplifted layers and the weaker sedimentary, reddish sandstone was eroded away and formed the present valleys. The degree of tilting of the dolerite can be measured. (Refer to diagram of the cross-section through the rock and notes of C. MacClintock.)
When the last glacier melted from New England (about 10,000 years ago), the big basaIt outcroppings remained. Rock fragments formed a composite deposit of unsorted sand and gravel, called till. This is the upper material that forms the bed of the Mill River. Later, when the sea rose, the big river mouth was formed. Later the rains brought down sediments into the river of sand, mud and peat forming the outwash meadow and salt marshes. Looking south from the bridge, or other vantage spots, you can see the remains of this once flourishing meadow where salt hay was collected. There are pictures of this in the teacher’s packet along with slides of this whole area.
There are geological clues as to the changes that have taken place with the Mill River. As a river matures and populations add problems of diverting streams, the size and direction of the river can change. Meandering is the term given when a river follows a crooked course and shows deposition of material on one side and erosion on the other forming a scarp or sharp edge (see diagram). As the water flows down the Mill River sediment is dropped. The largest rocks first and mud being deposited at the outer limits. When these deposits fan out on the valley floor it is called an alluvial fan. One can be seen on the left bank of the river near the Orange Street bridge (picture in the collection).
When you get to the dam you will notice the outcroping of traprock. There is a traprock or bedrock dike connecting Mill Rock on the west leading to the Whitney peak on the east, (see the Dana map of this dike). A dike is an igneous rock that is intruded across layers of sediments. This was a natural area for the original dam. It was here that more traprock was added to make the existing dam. Around the dam are two millstones from the days of the gristmill. There are two plates that show the profile of East Rock and the River.
Following the River to the Dam:
North by your map is looking up stream. You will find such plants as cattail, skunk cabbage, water arum, dogwood, multiflora rose, buttonbush, water shamrock, post oak and lovely plant life that adjusts to the areas many different sites.
Bird watching is a favorite of many people at East Rock all year. It is in a migratory path for many birds which stop to take a rest during their migrations. Warblers especially like this area.
The river has interesting fish life. From far up the river where trout may be caught to the flood gates where bass and killifish are caught, the Mill River provides many different kinds of places for many kinds of fish to live. Down from the Whitney Dam in the water weeds, can be found stickleback. Way downstream is a fish that prefers saltier water, the mummichog. This relative of the killifish can also live in pollution.
Mammals and reptiles thrive in the park. Look for footprints along the muddy part of the stream. Gnawed bark, clipped twigs might be clues. Most of the mammals are active at night. A turtle might easily be seen.
Other things to take note of:
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1. The beauty of the footbridge.
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2. The construction of the wooden covered bridge.
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3. Look across Whitney Avenue to the beautiful Whitney Barn.
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4. Compare the bridges with the picture of the original bridges (early map showing bridges).
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5. Look for the location of the new Whitney Museum.
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6. At the dam, look for the remains of the working areas of the Whitney Armory. (Photograph of this area and also slides available on loan and request.)
Remarks: This can be a most rewarding field trip and might influence some students to realize that we in New Haven have a remarkable amount of history and geology so close by and to help protect its natural beauty.
Eli Whitney Gun Factory and Dam (from Exploring East Rock Park)
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Lake Whitney
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East Rock Park
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Sill and Dike
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East Rock Park (Adapted from City of New Haven Engineer’s Map by Philip M. Orville)
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Cross Section of East Rock (East Rock Association)
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Cross Section through East Rock Sill and Dike—Views looking south
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