ife. Aquatic ecosystems and wildlife give humans early clear warning about the quality of the water environment upon which we all depend. For example, frogs, considered the “coal mine canaries” of the aquatic ecosystem, show signs early on of detrimental effects from human contaminants.
Waters from all of New HavenÍs streams, marsh creeks, and rivers drain into Long Island Sound which in turn drains into the Atlantic Ocean. The place where this fresh water drains into the salt water is called an estuary. Estuaries are semi-enclosed parts of the coastal ocean where sea water is diluted and mixed with fresh water coming from land. Our local rivers, harbors, and even Long Island Sound itself is all part of an estuarine system.
The word marsh has been defined as a treeless area of soft, wet land. To be a good marsh for wildlife it must be wet and it must have a varied balance of marsh plants that can support a population of small and larger animals which feed on the plants and on each other. Available food is not enough, the marsh must have a great variety of habitats in order to support a broad range of wildlife. It must have, deep water areas, shallow water areas, heavy vegetation on some of the shoreline, some bare areas on the shoreline, flooded grassy meadows, and dry grassy meadows. Marshy areas vary greatly. Some are permanent, some are temporary, some are freshwater, brakish water, or salt water, some are acidic, some are alkali, and they vary in size, depth, and in the forms of life they support. East Rock Park and Lighthouse Point have their own unique wetlands to study.
East Rock Park and Lighthouse Point Park both have a story to tell; it’s a record of what came before as well as what’s happening now. When you walk through the ranger station entrance to East Rock Park on the corner of Orange Street and Cold Spring Street and look up at the red sandstone around the base and up to the summit of East Rock along the traprock vertical ridges, think about the fact that these rocks are the result of molten material originating from below the earth’s crust moving up along cracks in the sandstone and solidifying into large sheets of black traprock otherwise known as dolerite. This happened approximately 170 million years ago. This traprock weathers to a brownish orange because of its iron content. Glacial activity created the final formations. Traprock resists erosion so hills were created. Streams of meltwater as the glacier receded were affected by the rise of the sea. This sent arms of rivers up beyond what is now North Haven. Sand and mud brought down by those rivers and peat formed in the salt marshes have since filled in those areas producing the flood plain through which the two rivers, the Mill and the Quinnipiac Rivers, wind their way towards New Haven Harbor and Long Island Sound. Beside the summit of East Rock are two other summits, Indian Head and Snake Rock, both formed by glacier activity. East Rock was quarried for its traprock for years. Many foundations of older New Haven homes were laid with East Rock traprock. The largest area quarried still visible is Corner Quarry, next to the Giant Steps leading to the summit.
College Woods, a level area near the Ranger Station, has gone through very few changes over the years. Many Indian artifacts found here have suggested this was the sight of a Quinnipiac village or camp sight long before the white settlers arrived in the New Haven area. Artifacts would include arrowheads, short bladed knives, and chisels. The Indians would use New Haven area rocks such as quartz, sandstone, and traprock to make these tools. They would also use rocks from other areas, west of the Hudson River, that flaked more easily such as jasper and black chert.
After years as a Quinnipiac hunting ground with the hills used as Indian lookouts, the white settlers arrived in this area. The Puritans attempted to establish a major commercial trading port. The area around the Mill River began to change rapidly. Grist Mills were built along the river and waterpowered by a low dam. In time Eli Whitne