"The lower Allegheny, from Oil City and Franklin (Venango County) downward, is first badly polluted, then it improves, and is again polluted to a very considerable degree. The chief source of pollution are the oil refineries at Oil City and Franklin. The injurious substances discharged into the river at these two places are simply amazing, and render the river entirely unfit for life; for thirty miles and more below there is not a mussel, not a crawfish, nor a fish able to live in this water. Then a gradual improvement begins in southern Venango County (pond snails, Physa and Goniobasis are present, also crawfishes begin to appear), and in northern Armstrong County conditions become almost normal. In spite of some additional pollution going into the river at Kittanning and Ford City (china factories), the good condition continues down to the point where the Kiskiminetas River discharges its mine water into the Allegheny from the left side. This destroys life on the left banks of the Allegheny, but conditions continue favorable on the right banks into Allegheny County, till we reach Natrona and Tarentum. Here additional pollution comes in the shape of salt water (salt works at Natrona) and the refuse of various mills, and this goes on all along the river down to where it unites with the Monongahela at Pittsburgh. Here the Allegheny is utterly polluted, and we have here possibly the greatest variety of pollution of any of the streams in the state.