Abstract
Dehloran plain, because of geographic location itself has always been one of the population centers in the southwest of Iran. Also, this area, because of permanent and seasonal rivers and fertile fields has been a good place to live in a long time. In terms of natural landscape, this plain is divisible into three regions of eastern, central and western. The first area (eastern area) is includes east of Dehloran plain, that consists of peaks and slopes of Zagros Mountains. The second area are including of lands near to these mountains. This area by floods of these mountains is covered with rocks and coarse-grained sediments. The third area (western area) is includes settlements from Neolithic to contemporary period and farming fields. Overall, these three areas for a long time, because of the rocky shelters in Zagros Mountains have been good place to live a human. On the other hand, these areas because of animals and suitable vegetation them, have been provider of food for human groups. Furthermore, because of existence conglomerate sediments eastern highlands of Dalpari in Dehloran, human access has been easy to rich sources of raw rock for make stone tools. This area that is more than 30 kilometers long, on the way of Zagros Mountains of Dalpari near to Dehloran plain and Dasht-e Abbas, covered with stone tools. These stone tools are containing of indicator samples of points, blades, centripetal core, Levallois chips. These samples can be sign of human existence at least from the middle Paleolithic period. So, existence of the Neolithic settlements to the late Islamic era is sign of a long process from the settlement human in this area.
Keywords: Zagros Mountains, Paleolithic, Dalpari, Dehloran.

Introduction
In 2015, in order to organize the western waters of the country, survey and identification programs frontier areas located in the provinces of Kermanshah and Ilam in format of ten programs for survey and identification (plan of tropical) were implemented. These programs were containing of identification water transfer routes, place of construction of dams, and drainage networks. The drainage network number 23 was studied by the author. This network was containing of Patk plain in Musian (eastern half of Dehloran), that water supply project it was on the agenda of the government. Therefore, all this plain with license number 943141/00/6495 with date of 2015/11/15 from Iranian center for archaeological research was carefully surveyed. During this survey (includes the southernmost tropical system in the south of the Ilam province), in addition to the identification of sites and ancient hills was surveyed wide area in the east of the plain that were many stone tools in it. The Dalpari area is several kilometers along the Zagros Mountains continue. The research background in relation to this area is shows the main focus of researchers on the sites belonging to the Neolithic period to the historic period and hasn’t been studied previous periods. The only survey of the Paleolithic period was done by Mohsen Zeynivand in year of 2015 in network number 22, that it has led to the identification and introduction of stone tools of type a Biface (Zeynivand, 2016 & 2017). So, the eastern half of Patk plain in Musian hasn’t been surveyed prior to this study. 

Introduction of identified traces 
A: Rock shelters
In a small part of the Dalpari Mountains a large number of small and large holes were identified with shelter form. These holes and shelters in sedimentary and conglomerate layers in low height hills have been formed with weak structure. The depth and width of the crater some of these holes and shelters 2 to 3 meters and high to 1.8 meters. Because of weak cement structure conglomerate and the existence of sedimentary layers of silicate and clay of non-condensing environmental degradation factors as wind and rain, it seems, these holes and shelters over time have been changed a lot. Due to a lot of stone tools inside and around of these sites, probably they were remnants of older refuges that used by humans (at least late) in the Paleolithic period. Today this area, because of a water fountain is used by pastoral nomads this area.

B: Surface finds
Mainly, at the surface of this area, can be seen stone tools includes blades, centripetal core, levallois chips, points, scrapers, and micro blades. The stone tools can be seen in all of plain, but in around the rivers less seen. Because of the continuity of distribution stone tools at surface this area, all of this range is introduced as a zone. During the survey this area, samples were collected from different parts of it. In total, 129 sites were encoded and distribution of the findings recorded. This area that is more than 30 kilometers long, on the way of Zagros Mountains of Dalpari near to Dehloran plain and Dasht-e Abbas, covered with stone tools. These stone tools are containing of indicator samples of points, blades, centripetal core, Levallois chips. Dating of samples collected is between 40,000 years and 16,000 years ago (Olszewski & Dibble, 1993).

Conclusion
Probably, dating stone tools collected of the Dalpari is between 40,000 years and 16,000 years ago. At most of surface the land in this area (except for a small area in the mountains) isn’t seen evidence of permanent deployment such as a cave or shelter. However, in these areas is identified little evidence of temporary and seasonal deployment of human in a small part of the northern mountains of the area. In this area, can be seen conglomerate and sedimentary layers, and because of the natural erosion including wind and rain have been created holes and shelters. These holes and shelters due to loose cement conglomerate and sedimentary layers is young seems to arrive, but stone tools around them doesn’t show this.