Passing node name created runtime to xsl:value-of select

My Input XML :

<Book>
    <Chapter>
        <Pages value="20" />
        <Note1Code value="1" />
        <Note1Description value="This is just for reference" />
        <Note1Level value="Avg" />

        <Note2Code value="2" />
        <Note2Description value="This is high important note" />
        <Note2Level value="Imp" />
    </Chapter>
</Book>

I want to transform into :

<Book>
    <Chapter>
        <Pages value="20" />

        <Note>
            <Code>1</Code>
            <Description>This is just for reference</Description>
            <Level>Avg</Level>
        </Note

        <Note>
            <Code>2</Code>
            <Description>This is high important note</Description>
            <Level>Imp</Level>
        </Note  
    </Chapter>
</Book>

Here is my XSLT :

<xsl:stylesheet version="1.0" xmlns:xsl="http://ift.tt/tCZ8VR">
<xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes"/>

    <xsl:template match="@* | node()">
       <xsl:copy>
         <xsl:apply-templates select="@* | node()"/>
       </xsl:copy>
    </xsl:template>
    <xsl:template match="*[substring(name(), 1, 4) = 'Note' and substring(name(),6) = 'Code']">

        <xsl:variable name="pdIdx" select="substring(name(), 5, 1)"/>
        <xsl:variable name="pdNode" select="concat('Note',$pdIdx,'Description/@value')"/>
        <xsl:variable name="pd" select="$pdNode"/>
        <Code>
            <xsl:value-of select="@value"/>
        </Code>
        <Description>
            <xsl:value-of select="$pdNode"/>
        </Description>
    </xsl:template>
</xsl:stylesheet>

I am trying to create the node name dynamically and then trying to get the value in select attribute. However, it is not working. The output is : The description tag is taking the node name and not its value

<Book>
    <Chapter>
        <Pages value="20"/>

        <Code>1</Code>
<Description>Note1Description/@value</Description>
        <Node1Description value="This is just for reference"/>
        <Note1Level value="Avg"/>

        <Code>2</Code>
<Description>Note2Description/@value</Description>
        <Node2Description value="This is high important note"/>
        <Note2Level value="Imp"/>
    </Chapter>
</Book>