c# XNA创建列表

我正试图制作一个列表来存储我的Trail类的所有实例，但它给了我以下错误:

可访问性不一致:字段类型为"System.Collections.Generic.list<Jumper"。Trail>'比' jump . main .trails'字段更难访问

我正在使用下面这行代码(它是错误的):

public static List<Trail> trails = new List<Trail>();

这是我的Trail.cs代码:

using System;
using System.Collections.Generic;
using System.Linq;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.GamerServices;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Media;
namespace Jumper
{
    public class Trail
    {
        public int width;
        public static float angle;
        //The current position of the Sprite
        public Vector2 pos = Vector2.Zero;
        //The texture object used when drawing the sprite
        public Texture2D trail;
        public Trail()
        {
            angle = Player.rotation;
            pos.X = Player.pos.X;
            pos.Y = Player.pos.Y;
        }
        //Load the texture for the sprite using the Content Pipeline
        public void LoadContent(ContentManager theContentManager, string theAssetName)
        {
            trail = theContentManager.Load<Texture2D>(theAssetName);
        }
        //Draw the sprite to the screen
        public void Draw(SpriteBatch theSpriteBatch)
        {
            theSpriteBatch.Draw(trail, new Vector2(pos.X, pos.Y), Color.White);
        }
        public void updateTrail()
        {
        }
    }
}

我做错了什么?